Hi, I have put a fresh install of Windows 7 RC 7100 64 bit onto a new system. After problems originally installing, I removed 1 stick and it installed fine. But now whenever I place 2 sticks in, the system crashes about 10-15 seconds after the 'Windows is loading' screen first appears. It boots fine with only 1 RAM module installed. I have tried both, matched, RAM sticks in each of my 4 slots on the MB, and singularly it will boot. Have had XP 32bit installed onto this setup with no problems with the memory (other than the 3GB limit...). All the drivers are up-to-date as is the BIOS. The BSOD flashes by so quick I can't read anything so don't know what error it is reporting. The system will boot fine with both sticks installed into safe mode, but not normally. I have run the memory diagnostic countless times, but still no problems reported. Does this sound like an OS problem or hardware? Can anyone help?? Thanks for your time.