Dumb questions:

Windows Vista 64bit home

Do you have WoW installed somewhere that it has permissions to write to? i.e. C:\Wow1 is probably not going to be easy going.

Are you running wow as administrator?

Less dumb questions:

Have you run a memory tester on your ram?

From my experience with brand spanky new machines, sometimes the ram timings can be out (dodgy ram, motherboard bios not quite ready) and this causes *random* freezes, blue screens, etc. PITA. Its been a while since I've tested some ram, maybe memtest is ready for your mobo/cpu:

http://www.memtest.org/