If that did not solve your problems of freezing it may be a intermittent piece of ram. I have had a problem like that before and it was bad RAM. Just a thought that might be useful.

Ok I see. Are you using windows xp home edition or professional edition? If you are using the home edition of XP you need to go in as the administrator in safemode and reset the password in the users...

Ahh... I have had this problem before. Hopefully you set up another account besides the Administrator account. Luckly I did. If you have more that one account on the machine you are going to want to...