Computer keeps shutting down!

Hi,
My computer, (Dell Inspiron 5100 XP Home sp3) keeps shutting down, if I try to run a scan (AVG) it shuts down. Sometimes it just shuts down in the middle of doing somthing. I thought I may be having HDD probs, so I formated the HDD reloaded Windows, and still had the same probs.
Okay, well I must be having HDD probs, installed new HDD, S.O.S.
My question is, are there any good software programs out there, that can analyze my computer and tell me whats up?
I've used hijack this, and removed a few things highlighted in red. Still S.O.S.
I supect I had a major virus, can a virus stay in your computer even after installing a new HDD? and if so how can I get rid of it, when it shuts down during a virus scan? Not just AVG, but any virus removal program I use, s&d, Avast, every online free virus scan.
Thank you for your help,
Steve

I supect I had a major virus, can a virus stay in your computer even after installing a new HDD?

No but if you saved your documents, settings, pictures or music and reinstalled them, you can get reinfected that way

Edited by garmanma, 22 September 2009 - 01:17 PM.

Hardware problems - such as bad RAM, overheating, bad power supply- can cause a computer to automatically shut down and/or restart. Run a live Linux CD (like Knoppix available here) for a while. If the shut-downs stop, the Windows partition is likely still infected.

Thank you for your responses.
I find it strange, that every time I try to run a virus scan, it shuts down in the middle of it. Last one was Terminator, got to about 60%, and shut down. Does the same thing with all virus scans I've run. This is really wierd.
How can I check my computer for bad hardware? I've run chkdsk, seems okay.
I tried to DL Knoppix, too complicated for me. I guess I could get a live disk.
Thank you again,
Steve

every time I try to run a virus scan, it shuts down in the middle of it

Sounds like the new rootkit that's making the rounds

You have a CPU over-heating problem, it would seem most likely. Use something like one of the following applications to monitor your CPU temperature while using the computer ....

Speedfan
http://majorgeeks.com/SpeedFan_d337.html

Motherboard Monitor
http://majorgeeks.com/download.php?det=311

Everest
http://majorgeeks.com/download4181.html
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You may also download and run toast.exe as a quick test of over-heating ...
http://majorgeeks.com/Toast_d867.html

Can you run this for 20 minutes without a problem? What temperatures are indicated for the CPU while running toast.exe for 20 minutes?
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FYI ... RE: the link you seem to be making to antivirus scans and the shutting down of your system, please have a look at the following thread on the AVG Free Forums, as an example ...
http://forums.avg.com/ww.avg-free-forum?se...ow&id=14141

Hi again, Thank you for your responses. I'm sorry there's so much time between my posts, but I've been spending hours, days even trying to get rid of this problem.
I think it may be that rootkit thing. I ran RootkitRevealer but naturally it shut down during the process.
Any suggestions will be appriciated.
Thanks again,
Steve
PS here is a screen shot of my event viewer. Note the red X's at the applications and system.
When I click on them, I get a window saying that the file is corrupt.

Edited by stevieg1969, 25 September 2009 - 12:51 PM.

Have you tired the suggested hardware diagnostics? This will save you TONS of time.

Before any more scans, run Prime95 ( http://majorgeeks.com/Prime95_d4363.html ) in safe mode to rule out overheating/ hardware issues.

Also, if you want, try running your scans in Safe Mode. You should have more luck there (unless its a really bad rootkit)