Help Please, My computer restarts on it's own

My computer restarts on it's own when I run a virus scan, Ad-aware scan, and when I try to downlowed program, including windows xp sp2, it won't even let me install it(I haven't tried downloading anything else). I hate having to work on my computers time and not the otherway around. I think it has something to do with Dumprep 0 -k, Because I disabled it from the startup, and it restarted my computer three times. I rechecked my startup and Dumprep 0 -k was checked again. Oh yea, I did do a HJT scan but I went to an autoreader and it said nothing was wrong. But I don't think the problem has anything to do with an installed program then it does a back door trojan or virus or something. Help please.

Please go here:

HijackThis Logs and Spyware/Malware Removal

Start a new topic, and copy/paste a current HijackThis! log into that thread.

Someone will check it out to see if your problems are related to "malware".