Still have a bet on memory, but normally after 12 hours memtest86+ catches something.
That said, memory that is not compatible with a board can do some strange things and yet still memtest86+(saw this once with a p35 board) did not see any error.
One thing maybe not covered yet, but is your cpu overclocked or overheating. Have you tested the cpu temperatures with something like hwmon. you can get many errors when a cpu is clock to high or overheating(but most times a cpu will just shut off).http://www.cpuid.com/softwares/hwmonitor.html
EDIT, you have a mouse pointer on your bsod?