Ok, obviously this isn't being caused by avg. Since it hasn't been installed for over two weeks now and the system is still crashing.
I've set the machine to not auto restart on crash, which doesn't appear to be working.
I've updated the bios to the latest and greatest available. As well as the intel chipset drivers
Memory tests: memtest (windows), lenovo's stress testing, and memtest86 all passed.
Stress Testing: Lenovo's software and prime95 with no failures. CPU temperature readings never exceeded 70c at full load, with the fans running at normal speed.
Windows Update pulls from a WSUS 3.x server on the local domain, polling every 22 hours (the max) and is set to reboot only when no users are logged in.
This machine has restarted three times since 12 am this morning with the same kernel-power event id 41, Task 63. Prior to this there were no recorded restarts since last week.
I was thinking that it might be something to do with windows update. The last update was installed on 7/20/2010. So, I'm not so sure about that now.
Also of note, there have been no BSODs since the last mentioned here. And, one time the system got stuck after it loaded classpnp.sys in safemode.
Any other ideas, etc.,?