The BIOS does a memory test before the graphics initiation. You should consider a stick is going bad. Try running on a single stick for a day, if you have two or more. Replace it with a the other stick if it fails and try that for a day. Make this the first check.
The other thought is you might need a higher wattage power supply.
Tell me here and now you’re not over clocking this system in anyway.
Well, since he didn’t know how to change the clock speed from the BIOS I’d guess not.
No I’m not overclocking anything. However, it’s interesting that you mention that, because when I can finally reboot after the crash, I usually get this message on the bios “Overclocking failed! Press f1 to enter setup or Press f2 to restore default values and continue…” I usually press f2 to restore defaults, but on the occasions I press f1 and go to check the bios, I can’t find any settings that are different than what I usually put them at. I am not 100% certain that I get this message with every mysterious shutdown/reboot, or that the shutdown/reboot gives me the message every time, I wasn’t keeping track.
There is something in my bios about cpu clock setting, but it’s on normal and locked to “prevent CPU from running at a lower multiplier setting”. So I have no idea what the bios thinks is overclocked (mem, graphics card, cpu?), why the overclocking failed, or how to find out. Any answers or ideas where to look would be appreciated. I’d be happy to write down my entire bios settings list and values and post them if you like.
I hate to break it to you, but I was getting that message too before my own board died. It’s sounding more and more like that’s your problem. Mine seems to have died a lot faster than yours, though. It only lasted about 4 days from first freeze to non-bootable death. Just long enough for me to run every single test and diagnostic I could think of.
Regarding the Ultimate Boot CD: Yes, it can be daunting to non-techies but you really only need to concern yourself with a memory test (Memtest86+), hard drive test (Drive Fitness) and CPU stress test (Mersenne Prime) and you don’t need to understand everything the diagnostics tell you, just look for error messages. They will run on an infinite loop until you manually stop them, but errors tend to show up relatively early. I think three successful passes is a good indicator that your RAM is okay. However, make sure you cover all your bases and do a hard drive scan (non-destructive only!!!) and CPU stress test. If the CPU is overheating, the stress test will definitely cause a crash.
If you have SpeedFan running, don’t just check the temps but also the measured output voltages. Your power supply shouldn’t stray more than + or - 1 volt, i.e. a range of values between 11v and 13v for a nominal 12v should be okay, anything else will indicate PS problems. However, SpeedFan relies on onboard sensors which can be unreliable, esp. for a dying mobo. The only way to be certain is to test with a multimeter as I described above.
Ok, the lights on the case started flickering when it shut off and restarted. I shut off the power supply switch on the back of the case, and it wouldn’t turn back on for about 10 minutes(!). So I got a new power supply and put it in. Then the Windoze hard drive started making constant strange clicking noises…
Wiped 2nd HD and installed Windoze on it. Been about 3 days now with no problems. I still think there may be issues with the mobo, but I’m going to wait and see what happens since I’m a bit low on cash right now.
Also, when I reinstalled, I managed to get my boot time down to about 20 seconds 
Constant clicking noises from hard drives are bad things and bad hard drives can/will cause all manner of problems.
Good. 