BSOD stop 0x00000124 intermittently on HTPC

So, I hit the BSOD again with the card out. That means the TV card isn't the problem. I'm now down to the motherboard, CPU, or power supply. I'm going to assume power supply at this point, since it seems the likely candidate based on manufacturer, age, etc. I've now removed the old power supply and replaced it with a new one. I also changed out the CPU fan - the old one was a 3 pin, and I had an OEM Intel 4-pin that it came from that was far less noisy. The thing runs significantly quieter, and so far I haven't had any problems. I'll reserve judgment for after I've run it for a week or so.

Well, couple of days and no BSOD. I also have the sleeping feature working correctly, thanks to MCE Standby Tool. Great little tool. I'm calling this fixed until I see otherwise. Thanks everyone!