Yes, it was a download tool for checking memory, not chkdsk/scandisk. Ok, if the power supply thing doesn't work I'll look at the Sandra option also.

>Just to be clear, when you talk about "MS's memory checking tool" you're referring to http://oca.microsoft.com/en/windiag.asp , not the hard drive CHKDSK/Scandisk function.
>
>I'd still be inclined to give Sandra a try, it might find something no-one's thought of yet.
>
>>Ok, thanks Al. Yes, I feel it is a hardware issue also. My next step is to swap in a borrowed power supply to test it. I will also look for any Asus BIOS updates.
>>
>>If it continues after that I will try the memory but I have run MS's memory checking tool in the past with no issues surfacing.
>>
>>Bill
>>
>>>It definitely sounds like a hardware problem, not a software problem.
>>>
>>>If the BIOS or other firmware on your motherboard has never been updated there is an excellent chance an update is available. Mobo builders usually rev the BIOS several times shortly after a board is released.
>>>
>>>Fabio brings up a good point, power supplies fail from time to time. There have been cases where large batches of bad capacitors were used in power supplies, which are now starting to fail. Power supplies are pretty standardized so it's not too hard to swap in a known good one to see if the problem goes away. Or you can take the cover off the one you have and check for any bulging/domed capacitors (do a GIS on "bulging capacitors" for examples)
>>>
>>>Bad RAM can cause this sort of problem. If your RAM is in 2 or more sticks you can temporarily remove one of them to see if the problem goes away (i.e. temporarily run with 1/2 the RAM)
>>>
>>>One tool that can help with intermittent problems is SiSoft Sandra (http://www.download.com/3000-2086-10018691.html) It includes various test modules and IIRC a "burn-in" module which loops continuously through a user-defined list of tests.
>>>
>>>>Hmmm, motherboard is Asus, don't remember number off hand, last three numbers are 333 though. I will check the web site for any updates but it's minimum 2 yrs old so I'd be surprised if there are any.
>>>>
>>>>I'll try to check the BIOS setting when I get a chance. Very frustrating.
>>>>
>>>>>Hi Bill,
>>>>>
>>>>>I had similar problem with MSI motherboard a while ago. I had to update BIOS and motherboard chipset drivers a few times to get it fixed.
>>>>>
>>>>>Usualy there's a settings or whole section called PC Health in the BIOS when motherboard provides protection from CPU overheating.
>>>>>
>>>>>>The issue showed up a relatively short time after I bought the machine. Took it back to them and they set it up and watched it and nothing happened ( naturally - customer support in the computer hardware industry just stinks :-( ). The problem was very intermittent and not often. But in recent days/weeks it has increased in frequency to be problematic. Fans are all running and I cleaned the various parts/ports of any accumulated dust. Is there a setting that can be checked to see if the motherboard has overheating protection?