I am in need of tech support. I have done everything I could short of replacing my drive and reinstalling XP. The situation is that my xp machine is shutting down maybe 30 minutes at a time on it's own. I recently noticed that the computer is now shutting down immediately after logging into xp. I am currently running Malwarebytes, CCleaner, and Microsoft Security Essentials. All of the softwares are up to date as of Saturday. I asked a co worker and he suggested that I may have a virus that shuts the system down. I ran a full scan with Microsoft Security Essentials and it reported no findings. With Malwarebytes, it said to be 2 threats but it was not able to complete the scan since the system is constantly shutting down. CCleaner noted no findings.

Yesterday I tried using Windows defender on a usb thumb drive. It also noted no findings and when I try to run a full scan, it shuts down.

Has anyone experienced or seen a virus take over when trying to run a full system scan on their anti virus software only to get turned off? And when you reboot, it just powers down? I am considering trying a different hard drive and try it in my xp machine. Thanks for any insight and support.