I have a Compaq Presario 3100, XP. It is very sick... to me anyway. I can not run a scan without it crashing and it tells me to contact the System Administrator. The last blue screen said something about BIOS updates and disable caching/shadowing. I can not run registry fixes, spybot -search and destroy, windows defender etc without it crashing. I can run my AVG tests. When I start it up I get the rectangular boxes and know that I have two items in the start up that show the rectangular boxes and HKCU\SOFTWARE\Microsoft|Windows NT\Current... I also have lots of cd drives listed - which I do not have. I try to remove them through the device manager in safemode - but they always return.

Please - what can I do? Thank you.

Sounds like you've got some malware on your PC.
I would recommend The Ultimate Boot CD (http://www.ultimatebootcd.com/)
You might also want to try Hijack This (http://www.spywareinfo.com/~merijn/programs.php). Be careful with HijackThis though, you can do more damage than good if you don't know what you're removing.

What is the exact crash error?
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