Binabik:

does it happen with a different virus-scanner, too?

diogenysos: No, it doesn't. I had Zone Alarm before but I didn't like it because it interfered with Ebay. Before that I had Norton and McAfee - none of them caused the computer to crash. After the first crash, I got a Microsoft message that said that the serious error occurred because of an anti-virus program.

Binabik: Its good to use an anti-virus-prog (e.g. AVG, Kaspersky, Norton, BitDefender etc.)
AND a firewall (ZoneAlarm, Keryo etc.).
WIndows XP and vista both have an integrated firewall.
People say that this integrated firewall is causing conflicts, so it can be turned off in the security-center of the xp-control-panel.
If your conflicts with AVG continue, the program should be uninstalled completely.
You might use a registry-cleaner (e.g. RegCleaner 4.3) to erase all AVG entries within the registry
in order to make sure there will be no conflicts any longer.

diogenysos: Thanks so much! I'll try turning the firewall off and see what happens. I assume that turning it off won't leave me open to disasters? Hmmm, would that leave me without a firewall at all? I'll have to check AVG and see if they have it.

Binabik: a firewall is a useful thing... .
turning the windows-firewall off means you do not have the control over the progs using the inernet - including possible "bad" ones.
its a good idea for sure to install another one, but step by step.
first you should solve your virus-scanner-problem.
as soon as you got one working fine on your computer, you may try to install a firewall, too.
if zoneAlarm didnt work well, try for example keryo... .

diogenysos: Again, thank you so much, I really appreciate the help! I'll follow your suggestions and let you know.

diogenysos: I disabled the firewall and the computer still crashed... I'll look into Keryo next....

Binabik:

well, this really looks as if you should wipe your AVG off and use an other antivirus-prog.

Binabik: As far as anti-virus software goes, I'd like to put in a good word for avast! home edition.
I've been a happy user for about 5 years, I think.

http://www.avast.com/eng/avast_4_home.html

wetware: Thank you very much, diogenysos and wetware! I'm currently using my son-in-laws computer but as soon as I get back to my own, I'll check out the avast site, it looks good!