I'm now getting a stop code on boot, : 0x0000007E.
As far as I can tell froma quick google that's something to do with a kernal mode driver? :|
Usually indicates hardware error, often memory.
There is a registry setting you can change to make Windows display the driver filename in the BSOD to help narrow down where the problem is.
If I remember correctly you had problems with the RAM when you installed Windows didn't you? My money would be on it being at fault.
:-|
Les Buggers, as they say in france.