I am running 2x4GB Ram in my computer. It would randomly freeze and the screen would go black or green, so I was advised to run a memtest. So far, it has 1 pass and is at 91% for the second, and it is at 18 hours of run time. It has been taking FOREVER. How long is it supposed to take to run the test? People say you want it to pass 5-6 times before calling it could. It would take 2-3 days to get there...