I just went thru this (one of my boxes did this habitually for weeks before I replaced the mb/cpu.) It had been working fine for months then started having issues so was really annoying. It started with intermittent hangs in Windows, then eventually it would lock up just where your's is. Turns out for me it was the CPU / MB / RAM combination. I took the CPU to another good working machine, and it started having the same problems. Once I took out some of the RAM it started working again. I suspect some of RAM just won't run reliably. (I had both Crucial and Corsair in these systems so not exactly brand X.) The sticks were all on the motherboard and CPU compatibility lists as well.
Even weirder, I noticed the slower clock speed CPU was fine, but as soon as I put in the faster clocked CPU, both systems would flake out. At one point while troubleshooting I even got another CPU and saw the same problem. This is with an Asus and Gigabyte AMD AM2+ based boards running their X2 CPUs. It was also a mix of 110w, 65w and 45w CPUs. Strangely the 110w would work reliabely while the lower power would not, so ruled out power issues. I am running the latest BIOS on all the boxes as well.
I eventually gave up and put in an Intel cpu/board and with the same ram and it's fine... though I much prefer AMD over Intel.
-Mike