Fatal error: the system has become unstable or is busy," it says. "Enter to return to Windows or press Control-Alt-Delete to restart your computer. If you do this you will lose any unsaved information in all open applications."
You have just been struck by the Blue Screen of Death. Anyone who uses Mcft Windows will be familiar with this. What can you do? More importantly, how can you prevent it happening?
1 Hardware conflict
The number one reason why Windows crashes is hardware conflict. Each hardware device communicates to other devices through an interrupt request channel (IRQ). These are supposed to be unique for each device.
For example, a printer usually connects internally on IRQ 7. The keyboard usually uses IRQ 1 and the floppy disk drive IRQ 6. Each device will try to hog a single IRQ for itself.
If there are a lot of devices, or if they are not installed properly, two of them may end up sharing the same IRQ number. When the user tries to use both devices at the same time, a crash can happen. The way to check if your computer has a hardware conflict is through the following route:
* Start-Settings-Control Panel-System-Device Manager.
Often if a device has a problem a yellow '!' appears next to its description in the Device Manager. Highlight Computer (in the Device Manager) and press Properties to see the IRQ numbers used by your computer. If the IRQ number appears twice, two devices may be using it.
Sometimes a device might share an IRQ with something described as 'IRQ holder for PCI steering'. This can be ignored. The best way to fix this problem is to remove the problem device and reinstall it.
Sometimes you may have to find more recent drivers on the internet to make the device function properly. A good resource is www.driverguide.com. If the device is a soundcard, or a modem, it can often be fixed by moving it to a different slot on the motherboard (be careful about opening your computer, as you may void the warranty).
When working inside a computer you should switch it off, unplug the mains lead and touch an unpainted metal surface to discharge any static electricity.
To be fair to Mcft, the problem with IRQ numbers is not of its making. It is a legacy problem going back to the first PC designs using the IBM 8086 chip. Initially there were only eight IRQs. Today there are 16 IRQs in a PC. It is easy to run out of them. There are plans to increase the number of IRQs in future designs.
2 Bad Ram
Ram (random-access memory) problems might bring on the blue screen of death with a message saying Fatal Exception Error. A fatal error indicates a serious hardware problem. Sometimes it may mean a part is damaged and will need replacing.
But a fatal error caused by Ram might be caused by a mismatch of chips. For example, mixing 70-nanosecond (70ns) Ram with 60ns Ram will usually force the computer to run all the Ram at the slower speed. This will often crash the machine if the Ram is overworked.
One way around this problem is to enter the BIOS settings and increase the wait state of the Ram. This can make it more stable. Another way to troubleshoot a suspected Ram problem is to rearrange the Ram chips on the motherboard, or take some of them out. Then try to repeat the circumstances that caused the crash. When handling Ram try not to touch the gold connections, as they can be easily damaged.
Parity error messages also refer to Ram. Modern Ram chips are either parity (ECC) or non parity (non-ECC). It is best not to mix the two types, as this can be a cause of trouble.
EMM386 error messages refer to memory problems but may not be connected to bad Ram. This may be due to free memory problems often linked to old Dos-based programmes.
3 BIOS settings
Every motherboard is supplied with a range of chipset settings that are decided in the factory. A common way to access these settings is to press the F2 or delete button during the first few seconds of a boot-up.
Once inside the BIOS, great care should be taken. It is a good idea to write down on a piece of paper all the settings that appear on the screen. That way, if you change something and the computer becomes more unstable, you will know what settings to revert to.
A common BIOS error concerns the CAS latency. This refers to the Ram. Older EDO (extended data out) Ram has a CAS latency of 3. Newer SDRam has a CAS latency of 2. Setting the wrong figure can cause the Ram to lock up and freeze the computer's display.
Mcft Windows is better at allocating IRQ numbers than any BIOS. If possible set the IRQ numbers to Auto in the BIOS. This will allow Windows to allocate the IRQ numbers (make sure the BIOS setting for Plug and Play OS is switched to 'yes' to allow Windows to do this.).
4 Hard disk drives
After a few weeks, the information on a hard disk drive starts to become piecemeal or fragmented. It is a good idea to defragment the hard disk every week or so, to prevent the disk from causing a screen freeze. Go to
* Start-Programs-Accessories-System Tools-Disk Defragmenter
This will start the procedure. You will be unable to write data to the hard drive (to save it) while the disk is defragmenting, so it is a good idea to schedule the procedure for a period of inactivity using the Task Scheduler.
The Task Scheduler should be one of the small icons on the bottom right of the Windows opening page (the desktop).
Some lockups and screen freezes caused by hard disk problems can be solved by reducing the read-ahead optimisation. This can be adjusted by going to
* Start-Settings-Control Panel-System Icon-Performance-File System-Hard Disk.
Hard disks will slow down and crash if they are too full. Do some housekeeping on your hard drive every few months and free some space on it. Open the Windows folder on the C drive and find the Temporary Internet Files folder. Deleting the contents (not the folder) can free a lot of space.
Empty the Recycle Bin every week to free more space. Hard disk drives should be scanned every week for errors or bad sectors. Go to
* Start-Programs-Accessories-System Tools-ScanDisk
Otherwise assign the Task Scheduler to perform this operation at night when the computer is not in use.
5 Fatal OE exceptions and VXD errors
Fatal OE exception errors and VXD errors are often caused by video card problems.
These can often be resolved easily by reducing the resolution of the video display. Go to
* Start-Settings-Control Panel-Display-Settings
Here you should slide the screen area bar to the left. Take a look at the colour settings on the left of that window. For most desktops, high colour 16-bit depth is adequate.
If the screen freezes or you experience system lockups it might be due to the video card. Make sure it does not have a hardware conflict. Go to
* Start-Settings-Control Panel-System-Device Manager
Here, select the + beside Display Adapter. A line of text describing your video card should appear. Select it (make it blue) and press properties. Then select Resources and select each line in the window. Look for a message that says No Conflicts.
If you have video card hardware conflict, you will see it here. Be careful at this point and make a note of everything you do in case you make things worse.
The way to resolve a hardware conflict is to uncheck the Use Automatic Settings box and hit the Change Settings button. You are searching for a setting that will display a No Conflicts message.
Another useful way to resolve video problems is to go to
* Start-Settings-Control Panel-System-Performance-Graphics
Here you should move the Hardware Acceleration slider to the left. As ever, the most common cause of problems relating to graphics cards is old or faulty drivers (a driver is a small piece of software used by a computer to communicate with a device).
Look up your video card's manufacturer on the internet and search for the most recent drivers for it.
6 Viruses
Often the first sign of a virus infection is instability. Some viruses erase the boot sector of a hard drive, making it impossible to start. This is why it is a good idea to create a Windows start-up disk. Go to
* Start-Settings-Control Panel-Add/Remove Programs
Here, look for the Start Up Disk tab. Virus protection requires constant vigilance.
A virus scanner requires a list of virus signatures in order to be able to identify viruses. These signatures are stored in a DAT file. DAT files should be updated weekly from the website of your antivirus software manufacturer.
An excellent antivirus programme is McAfee VirusScan by Network Associates ( www.nai.com). Another is Norton AntiVirus 2000, made by Symantec ( www.symantec.com).
7 Printers
The action of sending a document to print creates a bigger file, often called a postscript file.
Printers have only a small amount of memory, called a buffer. This can be easily overloaded. Printing a document also uses a considerable amount of CPU power. This will also slow down the computer's performance.
If the printer is trying to print unusual characters, these might not be recognised, and can crash the computer. Sometimes printers will not recover from a crash because of confusion in the buffer. A good way to clear the buffer is to unplug the printer for ten seconds. Booting up from a powerless state, also called a cold boot, will restore the printer's default settings and you may be able to carry on.
8 Software
A common cause of computer crash is faulty or badly-installed software. Often the problem can be cured by uninstalling the software and then reinstalling it. Use Norton Uninstall or Uninstall Shield to remove an application from your system properly. This will also remove references to the programme in the System Registry and leaves the way clear for a completely fresh copy.
The System Registry can be corrupted by old references to obsolete software that you thought was uninstalled. Use Reg Cleaner by Jouni Vuorio to clean up the System Registry and remove obsolete entries. It works on Windows 95, Windows 98, Windows 98 SE (Second Edition), Windows Millennium Edition (ME), NT4 and Windows 2000.
Read the instructions and use it carefully so you don't do permanent damage to the Registry. If the Registry is damaged you will have to reinstall your operating system. Reg Cleaner can be obtained from www.jv16.org
Often a Windows problem can be resolved by entering Safe Mode. This can be done during start-up. When you see the message "Starting Windows" press F4. This should take you into Safe Mode.
Safe Mode loads a minimum of drivers. It allows you to find and fix problems that prevent Windows from loading properly.
Sometimes installing Windows is difficult because of unsuitable BIOS settings. If you keep getting SUWIN error messages (Windows setup) during the Windows installation, then try entering the BIOS and disabling the CPU internal cache. Try to disable the Level 2 (L2) cache if that doesn't work.
Remember to restore all the BIOS settings back to their former settings following installation.
9 Overheating
Central processing units (CPUs) are usually equipped with fans to keep them cool. If the fan fails or if the CPU gets old it may start to overheat and generate a particular kind of error called a kernel error. This is a common problem in chips that have been overclocked to operate at higher speeds than they are supposed to.
One remedy is to get a bigger better fan and install it on top of the CPU. Specialist cooling fans/heatsinks are available from www.computernerd.com or www.coolit.com
CPU problems can often be fixed by disabling the CPU internal cache in the BIOS. This will make the machine run more slowly, but it should also be more stable.
10 Power supply problems
With all the new construction going on around the country the steady supply of electricity has become disrupted. A power surge or spike can crash a computer as easily as a power cut.
If this has become a nuisance for you then consider buying a uninterrupted power supply (UPS). This will give you a clean power supply when there is electricity, and it will give you a few minutes to perform a controlled shutdown in case of a power cut.
It is a good investment if your data are critical, because a power cut will cause any unsaved data to be lost.
31 March, 2008
A Guide to Internet Security: Becoming an Uebercracker
This is a paper will be broken into two parts, one showing 15 easy steps
to becoming a uebercracker and the next part showing how to become a
ueberadmin and how to stop a uebercracker. A uebercracker is a term phrased
by Dan Farmer to refer to some elite (cr/h)acker that is practically
impossible to keep out of the networks.
Here's the steps to becoming a uebercracker.
Step 1. Relax and remain calm. Remember YOU are a Uebercracker.
Step 2. If you know a little Unix, you are way ahead of the crowd and skip
past step 3.
Step 3. You may want to buy Unix manual or book to let you know what
ls,cd,cat does.
Step 4. Read Usenet for the following groups: alt.irc, alt.security,
comp.security.unix. Subscribe to Phrack@well.sf.ca.us to get a background
in uebercracker culture.
Step 5. Ask on alt.irc how to get and compile the latest IRC client and
connect to IRC.
Step 6. Once on IRC, join the #hack channel. (Whew, you are half-way
there!)
Step 7. Now, sit on #hack and send messages to everyone in the channel
saying "Hi, Whats up?". Be obnoxious to anyone else that joins and asks
questions like "Why cant I join #warez?"
Step 8. (Important Step) Send private messages to everyone asking for new
bugs or holes. Here's a good pointer, look around your system for binary
programs suid root (look in Unix manual from step 3 if confused). After
finding a suid root binary, (ie. su, chfn, syslog), tell people you have a
new bug in that program and you wrote a script for it. If they ask how it
works, tell them they are "layme". Remember, YOU are a UeberCracker. Ask
them to trade for their get-root scripts.
Step 9. Make them send you some scripts before you send some garbage file
(ie. a big core file). Tell them it is encrypted or it was messed up and
you need to upload your script again.
Step 10. Spend a week grabbing all the scripts you can. (Dont forget to be
obnoxious on #hack otherwise people will look down on you and not give you
anything.)
Step 11. Hopefully you will now have atleast one or two scripts that get
you root on most Unixes. Grab root on your local machines, read your
admin's mail, or even other user's mail, even rm log files and whatever
temps you. (look in Unix manual from step 3 if confused).
Step 12. A good test for true uebercrackerness is to be able to fake mail.
Ask other uebercrackers how to fake mail (because they have had to pass the
same test). Email your admin how "layme" he is and how you got root and how
you erased his files, and have it appear coming from satan@evil.com.
Step 13. Now, to pass into supreme eliteness of uebercrackerness, you brag
about your exploits on #hack to everyone. (Make up stuff, Remember, YOU are
a uebercracker.)
Step 14. Wait a few months and have all your notes, etc ready in your room
for when the FBI, Secret Service, and other law enforcement agencies
confinscate your equipment. Call eff.org to complain how you were innocent
and how you accidently gotten someone else's account and only looked
because you were curious. (Whatever else that may help, throw at them.)
Step 15. Now for the true final supreme eliteness of all uebercrackers, you
go back to #hack and brag about how you were busted. YOU are finally a
true Uebercracker.
Now the next part of the paper is top secret. Please only pass to trusted
administrators and friends and even some trusted mailing lists, Usenet
groups, etc. (Make sure no one who is NOT in the inner circle of security
gets this.)
This is broken down on How to Become an UeberAdmin (otherwise know as a
security expert) and How to stop Uebercrackers.
Step 1. Read Unix manual ( a good idea for admins ).
Step 2. Very Important. chmod 700 rdist; chmod 644 /etc/utmp. Install
sendmail 8.6.4. You have probably stopped 60 percent of all Uebercrackers
now. Rdist scripts is among the favorites for getting root by
uebercrackers.
Step 3. Okay, maybe you want to actually secure your machine from the
elite Uebercrackers who can break into any site on Internet.
Step 4. Set up your firewall to block rpc/nfs/ip-forwarding/src routing
packets. (This only applies to advanced admins who have control of the
router, but this will stop 90% of all uebercrackers from attempting your
site.)
Step 5. Apply all CERT and vendor patches to all of your machines. You have
just now killed 95% of all uebercrackers.
Step 6. Run a good password cracker to find open accounts and close them.
Run tripwire after making sure your binaries are untouched. Run tcp_wrapper
to find if a uebercracker is knocking on your machines. Run ISS to make
sure that all your machines are reasonably secure as far as remote
configuration (ie. your NFS exports and anon FTP site.)
Step 7. If you have done all of the following, you will have stopped 99%
of all uebercrackers. Congrads! (Remember, You are the admin.)
Step 8. Now there is one percent of uebercrackers that have gained
knowledge from reading some security expert's mail (probably gained access
to his mail via NFS exports or the guest account. You know how it is, like
the mechanic that always has a broken car, or the plumber that has the
broken sink, the security expert usually has an open machine.)
Step 9. Here is the hard part is to try to convince these security experts
that they are not so above the average citizen and that by now giving out
their unknown (except for the uebercrackers) security bugs, it would be a
service to Internet. They do not have to post it on Usenet, but share
among many other trusted people and hopefully fixes will come about and
new pressure will be applied to vendors to come out with patches.
Step 10. If you have gained the confidence of enough security experts,
you will know be a looked upto as an elite security administrator that is
able to stop most uebercrackers. The final true test for being a ueberadmin
is to compile a IRC client, go onto #hack and log all the bragging and
help catch the uebercrackers. If a uebercracker does get into your system,
and he has used a new method you have never seen, you can probably tell
your other security admins and get half of the replies like - "That bug
been known for years, there just isn't any patches for it yet. Here's my
fix." and the other half of the replies will be like - "Wow. That is very
impressive. You have just moved up a big notch in my security circle."
VERY IMPORTANT HERE: If you see anyone in Usenet's security newsgroups
mention anything about that security hole, Flame him for discussing it
since it could bring down Internet and all Uebercrackers will now have it
and the million other reasons to keep everything secret about security.
Well, this paper has shown the finer details of security on Internet. It has
shown both sides of the coin. Three points I would like to make that would
probably clean up most of the security problems on Internet are as the
following:
1. Vendors need to make security a little higher than zero in priority.
If most vendors shipped their Unixes already secure with most known bugs
that have been floating around since the Internet Worm (6 years ago) fixed
and patched, then most uebercrackers would be stuck as new machines get
added to Internet. (I believe Uebercracker is german for "lame copy-cat
that can get root with 3 year old bugs.") An interesting note is that
if you probably check the mail alias for "security@vendor.com", you will
find it points to /dev/null. Maybe with enough mail, it will overfill
/dev/null. (Look in manual if confused.)
2. Security experts giving up the attitude that they are above the normal
Internet user and try to give out information that could lead to pressure
by other admins to vendors to come out with fixes and patches. Most
security experts probably don't realize how far their information has
already spread.
3. And probably one of the more important points is just following the
steps I have outlined for Stopping a Uebercracker.
Resources for Security:
Many security advisories are available from anonymous ftp cert.org.
Ask archie to find tcp_wrapper, security programs. For more information
about ISS (Internet Security Scanner), email cklaus@shadow.net.
to becoming a uebercracker and the next part showing how to become a
ueberadmin and how to stop a uebercracker. A uebercracker is a term phrased
by Dan Farmer to refer to some elite (cr/h)acker that is practically
impossible to keep out of the networks.
Here's the steps to becoming a uebercracker.
Step 1. Relax and remain calm. Remember YOU are a Uebercracker.
Step 2. If you know a little Unix, you are way ahead of the crowd and skip
past step 3.
Step 3. You may want to buy Unix manual or book to let you know what
ls,cd,cat does.
Step 4. Read Usenet for the following groups: alt.irc, alt.security,
comp.security.unix. Subscribe to Phrack@well.sf.ca.us to get a background
in uebercracker culture.
Step 5. Ask on alt.irc how to get and compile the latest IRC client and
connect to IRC.
Step 6. Once on IRC, join the #hack channel. (Whew, you are half-way
there!)
Step 7. Now, sit on #hack and send messages to everyone in the channel
saying "Hi, Whats up?". Be obnoxious to anyone else that joins and asks
questions like "Why cant I join #warez?"
Step 8. (Important Step) Send private messages to everyone asking for new
bugs or holes. Here's a good pointer, look around your system for binary
programs suid root (look in Unix manual from step 3 if confused). After
finding a suid root binary, (ie. su, chfn, syslog), tell people you have a
new bug in that program and you wrote a script for it. If they ask how it
works, tell them they are "layme". Remember, YOU are a UeberCracker. Ask
them to trade for their get-root scripts.
Step 9. Make them send you some scripts before you send some garbage file
(ie. a big core file). Tell them it is encrypted or it was messed up and
you need to upload your script again.
Step 10. Spend a week grabbing all the scripts you can. (Dont forget to be
obnoxious on #hack otherwise people will look down on you and not give you
anything.)
Step 11. Hopefully you will now have atleast one or two scripts that get
you root on most Unixes. Grab root on your local machines, read your
admin's mail, or even other user's mail, even rm log files and whatever
temps you. (look in Unix manual from step 3 if confused).
Step 12. A good test for true uebercrackerness is to be able to fake mail.
Ask other uebercrackers how to fake mail (because they have had to pass the
same test). Email your admin how "layme" he is and how you got root and how
you erased his files, and have it appear coming from satan@evil.com.
Step 13. Now, to pass into supreme eliteness of uebercrackerness, you brag
about your exploits on #hack to everyone. (Make up stuff, Remember, YOU are
a uebercracker.)
Step 14. Wait a few months and have all your notes, etc ready in your room
for when the FBI, Secret Service, and other law enforcement agencies
confinscate your equipment. Call eff.org to complain how you were innocent
and how you accidently gotten someone else's account and only looked
because you were curious. (Whatever else that may help, throw at them.)
Step 15. Now for the true final supreme eliteness of all uebercrackers, you
go back to #hack and brag about how you were busted. YOU are finally a
true Uebercracker.
Now the next part of the paper is top secret. Please only pass to trusted
administrators and friends and even some trusted mailing lists, Usenet
groups, etc. (Make sure no one who is NOT in the inner circle of security
gets this.)
This is broken down on How to Become an UeberAdmin (otherwise know as a
security expert) and How to stop Uebercrackers.
Step 1. Read Unix manual ( a good idea for admins ).
Step 2. Very Important. chmod 700 rdist; chmod 644 /etc/utmp. Install
sendmail 8.6.4. You have probably stopped 60 percent of all Uebercrackers
now. Rdist scripts is among the favorites for getting root by
uebercrackers.
Step 3. Okay, maybe you want to actually secure your machine from the
elite Uebercrackers who can break into any site on Internet.
Step 4. Set up your firewall to block rpc/nfs/ip-forwarding/src routing
packets. (This only applies to advanced admins who have control of the
router, but this will stop 90% of all uebercrackers from attempting your
site.)
Step 5. Apply all CERT and vendor patches to all of your machines. You have
just now killed 95% of all uebercrackers.
Step 6. Run a good password cracker to find open accounts and close them.
Run tripwire after making sure your binaries are untouched. Run tcp_wrapper
to find if a uebercracker is knocking on your machines. Run ISS to make
sure that all your machines are reasonably secure as far as remote
configuration (ie. your NFS exports and anon FTP site.)
Step 7. If you have done all of the following, you will have stopped 99%
of all uebercrackers. Congrads! (Remember, You are the admin.)
Step 8. Now there is one percent of uebercrackers that have gained
knowledge from reading some security expert's mail (probably gained access
to his mail via NFS exports or the guest account. You know how it is, like
the mechanic that always has a broken car, or the plumber that has the
broken sink, the security expert usually has an open machine.)
Step 9. Here is the hard part is to try to convince these security experts
that they are not so above the average citizen and that by now giving out
their unknown (except for the uebercrackers) security bugs, it would be a
service to Internet. They do not have to post it on Usenet, but share
among many other trusted people and hopefully fixes will come about and
new pressure will be applied to vendors to come out with patches.
Step 10. If you have gained the confidence of enough security experts,
you will know be a looked upto as an elite security administrator that is
able to stop most uebercrackers. The final true test for being a ueberadmin
is to compile a IRC client, go onto #hack and log all the bragging and
help catch the uebercrackers. If a uebercracker does get into your system,
and he has used a new method you have never seen, you can probably tell
your other security admins and get half of the replies like - "That bug
been known for years, there just isn't any patches for it yet. Here's my
fix." and the other half of the replies will be like - "Wow. That is very
impressive. You have just moved up a big notch in my security circle."
VERY IMPORTANT HERE: If you see anyone in Usenet's security newsgroups
mention anything about that security hole, Flame him for discussing it
since it could bring down Internet and all Uebercrackers will now have it
and the million other reasons to keep everything secret about security.
Well, this paper has shown the finer details of security on Internet. It has
shown both sides of the coin. Three points I would like to make that would
probably clean up most of the security problems on Internet are as the
following:
1. Vendors need to make security a little higher than zero in priority.
If most vendors shipped their Unixes already secure with most known bugs
that have been floating around since the Internet Worm (6 years ago) fixed
and patched, then most uebercrackers would be stuck as new machines get
added to Internet. (I believe Uebercracker is german for "lame copy-cat
that can get root with 3 year old bugs.") An interesting note is that
if you probably check the mail alias for "security@vendor.com", you will
find it points to /dev/null. Maybe with enough mail, it will overfill
/dev/null. (Look in manual if confused.)
2. Security experts giving up the attitude that they are above the normal
Internet user and try to give out information that could lead to pressure
by other admins to vendors to come out with fixes and patches. Most
security experts probably don't realize how far their information has
already spread.
3. And probably one of the more important points is just following the
steps I have outlined for Stopping a Uebercracker.
Resources for Security:
Many security advisories are available from anonymous ftp cert.org.
Ask archie to find tcp_wrapper, security programs. For more information
about ISS (Internet Security Scanner), email cklaus@shadow.net.
