Intermittent Computer Lock-up

[sub_shark]

So here is my problem:

Every couple hours or so, no real defined time, my computer locks up hard. Anything I try to do takes the computer minutes of real time, and eventually after anywhere from 5-15 minutes, it completely runs normally, no problems whatsoever.

Intel Core i7 930@2.8Ghz
6GB RAM
64 Bit Windows 7
Geforce GTX 470


I have run a virus scan, found nothing. I look at event viewer, and there are so many errors, informational updates, and warnings I have no idea which could lead me to the real problem. I have 2 Western Digital Hard drives, and have run the proprietary scan software they provide, as well as ran Acronis Drive Monitor which hasn't picked anything up. I have also replaced my motherboard which did not fix the problem.

Any help would be much appreciated, as I am getting close to lighting the damn thing on fire.

 

[PG]

What is the cpu temp?
What heatsink do you use?
How is the airflow in the case? How many and what sized fans do you have?
yes, it sounds like a heat problem if you could not guess where I'm going with these questions

 

[sm625]

Check your interrupt counter. It probably goes off the charts when this happens. Some driver has to be the cause. Make a backup drive, then start stripping out drivers, including the video card and ethernet drivers, until the problem goes away.

 

[sub_shark]

Cpu Temps range between 55C and 50C for the 4 cores when it happens. I use the standard Heatsink that came with my i7 chip. I have an Antec 902 case, with 3 120mm fans and the single 200mm fan. I have blown out the case with compressed air, there is no dust in it anywhere.

Where does one check the interrupt counter?