Operating System,Drivers & A Highly Likely Culprit

Operating System
Early versions of Windows have some bugs, (errors in the way it was written), that can cause intermittent problems. For instance, the first version of Windows 95 had a problem with one of its components called "Kernel32.dll" this error manifested its self on only some computers when trying to connect to the Internet. Subsequent upgrades cured this problem. Windows 98-SE, the second release of Windows 98 is by far the most bug free and stable version of Windows yet, (But only if it was professionally installed on your computer). Generally, if your computer came with Windows 98-SE, installed from the factory, It's more stable than an older machine that has been upgraded from Windows 95.
Windows 95 & 98 has a database of information "The Registry" that controls how windows and all the programs should operate and cooperate with each other. As new programs are added and old programs are removed, the registry can become damaged. Many times this damage will cause the computer to become unstable. More freezes and error messages. Some times the only solution to this kind of problem is to completely clean your hard drive and reinstall the operating system and all other programs.
( See: Starting Over )



Drivers
Drivers are little programs written by the manufacture of a given component like video cards, sound cards, modems and so forth. These drivers are installed in, and become part of, the operating system. Errors in drivers or older versions of these critical components can cause many intermittent problems.

Nobody makes all their own parts. Not even IBM, Compaq, Dell, or any other computer manufacture makes all the parts in their computer systems. Every computer manufacture buys their video cards from one manufacture, and their modems from another, and their main boards and memory from yet other manufactures. This can, and does, cause problems. A manufacture of say a video card ships thousands of a given model to a major computer manufacture, then the computer company uses these to build thousands of computers. Well after the computers are built and sold to the end user, the video card manufacture discovers a bug in their drivers. The owner of this computer is now stuck with buggy drivers. Do you think any of the big guys are going to go out of their way to inform all their customers of the faulty drivers and help them obtain new ones? Unlikely.

An odd problem related to drivers and background programs may cause your computer to seemingly boot up OK, but when you move your mouse to, and double-click an icon, nothing happens. Try uninstalling your printer, then test your computer. If all is well, contact the printer company for new drivers. (If you have an HP InkJet, ask the company how to install the drivers in the "Non-Bi-directional mode.".)




A Highly Likely Culprit
If you're experiencing Fatal Exception Errors, what we call the "Blue Screen Of Death" or BSOD, more times than not it's due to the video driver. Often after installing a new program or upgrading an old one, the new code will make demands on the video driver that the original driver can't handle properly. This results in a very unstable computer. Finding the EXACT make and model of your video card, then downloading, and installing, the latest drivers from the company's web site may fix the problem.
Use Caution!
Backup all your important data before installing any drivers. Wrong or buggy drivers can turn a running computer into a doorstop.