I've got a Windows 7 machine that is locking up randomly. It can be in the first thirty seconds, or it can be hours later. There is nothing specific I can find that is running when it happens. When it locks, the screen doesn't change, but nothing moves. The waiting icon stops, the mouse stops, keyboard doesn't work, etc. I've even tried the crash on ctrl-scrl registry hack, and it won't even dump the kernel. I've run hardware diagnostics on the RAM and it doesn't find any problems. I would think it is a hardware issue, but on this exact same machine, I can run 64 Bit Ubuntu and it has zero problems. I've even tried reinstalling Windows7 from scratch, and it still happens.
Anyone have any ideas? Any good diagnostic tools to recommend?
Edit: 15Jun - The machine is my home built machine from various parts. It has a Gigabyte MA790X-UD4P motherboard, corsair RAM, NVidia video. It was running like a champ until my HDD took a dump. I had to send it back to Seagate and I went to Fry's to get a new one. I put the new drive in, and loaded Win7 on it. That's when it started locking up. But like I said, it runs without issue on Ubuntu 10.04.
Edit: 17Jun - Well, I removed two sticks of RAM and only left 4GB, and it hasn't crashed on me yet. So I'm thinking that it had something to do with a RAM mismatch. Even though MEMTEST passed with flying colors, it fixed it.
Next step is to try and add a couple more 2 GB sticks instead of the 512's that I had in there.