My computer restarts without any warning. Help Please?

Okay so one day my computer was working fine. Then when i inserted a CD which contained pictures and some other stuff, My computer started getting slow and lagging. I ran some scans but nothing came up. The computer then started restarting on its own, giving me no error message and no Blue Screen. I right clicked my computer--%26gt; properties--%26gt;and uncliked []RESTART AUTOMATICALLY.But I found out that it still restarts. Now the puzzling thing is that it has no particular time patern to restart but only when i go to Start--%26gt;run and type anything (msconfig, or chkdsk C: /f, cmd) it restarts and when i try to download an antivirus software it resarts. It also restarts when i try to look for which .exe process can be a virus online.(e.g when i search smss.exe or lsass.exe on websites)

Someone told me to go to Start--%26gt;run type msconfig and Disable all process. After doing this I cant loggin yahoo or hotmail or anything. I cant use my scanner.Now i cant undo

Im on Wndows xP sp2. HELP!

My computer restarts without any warning. Help Please?

Many, many time these types of problems are due to corrupted files within the Windows startup files, etc. What I'd recommend you do is a "repair" installation of Windows.

Give this a shot.

REPAIRING OR REINSTALLING WINDOWS XP

Turn your PC on and insert the Windows XP disk into the CD/DVD drive.

Reboot/restart the PC. This will cause the PC to boot from the XP disk and not the hard drive..