Bizarre lockup problem

I've been having a weird problem with my new rig for the past few days. Since Monday, it has been randomly locking up. Just freezing solid, forcing a cold reboot. It's less than a month old, and I have only done a test OC to 3800 and it was stable with the core voltage at only 1.34. I have since brought it back down to stock almost two weeks ago now.

I had a couple of gadgets installed, a drive meter and a network meter since the weekend. The event manager shows a couple of things failing to start right before the freeze up. I'm currently on the wife's machine while mine runs Memtest86 overnight, so I can't post any event log details.

The bulk of my problems started when I set up my home server to share with this machine, and I allowed the files to be accessed offline. Windows has done a sync operation, and every time it does, I can guarantee a freeze up. The event log for those freezes says I have a controller error on hard disk 3. I don't have a hard disk 3. I have 0, 1 and 2, and a DVD drive on SATA port 6 which was not in use at the time.

I have rolled back to Monday using a system restore, and the server was offline tonight. I have disabled almost everything unnecessary, yet I still got a freeze up while editing a post here about an hour ago (Firefox). When I rebooted, MS Essentials came up offline, and said it failed to start. I had to start it manually. I also can't seem to find a good Vcore for the CPU, and when I put it to auto, it wound up being over 1.4V. Yikes!

Does anybody have any ideas on any Windows issue that can cause this? Or am I looking at a beginning to be bricked motherboard?

Thanks.

64-bit ralink wireless driver? Network drivers on 64 have caused this again and again. Might want to check that out...

Turns out it's either the CPU, motherboard, or RAM. It's definitely hardware. Memtest86 stopped dead at just over one hour. I relaxed the RAM timings and it stopped at 35 minutes. No errors, just frozen solid.

I've put the whole thing back at default, except for the necessary boost to the RAM voltage, and I'll try tonight after work. I'm really hoping it isn't the CPU. Everything else is still under warranty.

EDIT: Swapped RAM slots and ran them at 1066 on Memtest86 for 4 hours. No freeze ups. Pretty sure it's a RAM issue.