My PC is infected with some sort of virus, but is undetected by AVG, Zone Alarm, Norton and Kaspersky. About 50 seconds after login, There is an automatic shutdown and it will reboot again. Unlike the known worms, the shutdown is instant and is not detected. I have checked all my start-up files and everything else I suspected was the problem, but there is nothing that seems the least bit suspicious.

try unchecking automatically restart and you should get an error message when it shuts down.

Hopefully my advice will help you...Please post back with your results....thanks

I have already disabled automatic restart, but the shutdown acts instantly as if the power was out. I am in safe trying to fix the problem. The shutdown does not trigger any errors.

That's about all I can suggest without knowing an error, maybe someone else has some ideas?

Hopefully my advice will help you...Please post back with your results....thanks

I haved instant shut downs like yours when I had problem with my ATI video card.But I think it's a different problem here with your computer. :)

Thanks all who helped me :

From what your describing it almost sounds like a hardware issue rather than a virus. Processor could be getting to hot. To be sure you will have to preform at least a destructive recovery on your system and you will want to back up any important data/files that you cannot live without.

After preforming a recovery and the issue is still there then we know it's hardware at fault.

Go to http://www.hp.com/ and type in the search field "bph07145". Make sure that only your keyboard, mouse, monitor and power cable are connected durring the recovery or the recovery will fail.

If your pc is under warrenty than HP will repair it.

If your computer says, "Printer out of Paper," this problem cannot be resolved by continuously clicking the "OK" button.

A system recovery is a simple solution, but I wish to fix the problem without doing so. I have checked my hardware and they all seemed fine. If my computer was overheated wouldn't it crash during safe mode?

About the error message XpUser4Real was requesting, it did indeed appear after tweaking some settings.

- A problem has been detected and windows had been shutdown to prevent damge to your computer.

DRIVER_IRQL_NOT_LESS_OR_EQUAL

Technical Information:

*** STOP: 0x00000001 (0x00001118, 0x00000002, 0x00000000, 0xF6DC919E)

*** Rt7nicxp.sys - Address F6DC919E base at F6DBF000, DateStamp 416f73d

http://www.tek-tips.com/viewthread.cfm?qid=308429

That page has lots of different solutions, maybe there's one for you

Hopefully my advice will help you...Please post back with your results....thanks