My computer keeps shutting down...help please!

My computer shuts down unexpectedly...no warnings no error messages. I just installed Windows 7 successfully and it shut down after a few minutes online. Sometimes it shuts down after 2 or 3 minutes, sometimes longer. I was hoping it was a virus, so I did a clean install with Windows 7. Looks like that didn't help. Could it be the hard drive? Is there any way to troubleshoot what the problem could be? Could something inside the computer be loose? Any help would be really appreciated!

It is more likely to be a hardware issue than anything else. I'd suspect and check three things:

1. Overheating
2. Power supply issues.
3. Bad RAM.

This solved my problem.  I had a friend install Win 7, to replace Win XP, and she added some RAM.  This was not happening before the install, so I switched out the power supply (300W to 450W) thinking it needed more power.  Came across this solution and a light came on when I saw #3 bad RAM.  I pulled the RAM and my computer is immediately 10X's faster and it's not cutting off.  Thanks.

Hi friend,

This problem may be for temperature or may be hardware issue. So please check frist temperature and then check SMPS. can you check its working in BIOS screen. Is it power off in BIOS screen or not..?

Regards

Raj

I had the same with my lap top I was told it is overheating so I turned it upside down and had a look at the bottom air vent, and sure enough the air vent were blocked up, I hoovered them and unblocked them and this done the trick. my laptop has been good as gold and not shut down.

I start running my security's that I have setup and it just shut's down does not restart

by the way it is a new refurbished hp desktop  computer I have only had this computer for 2 weeks came w\windows 7 and I changed to windows 10