New Build BSOD

Hi, I just built a new system (first time) and i keep getting Blue Screen.
my specs are Abit IN9-32max motherboard, Intel E6600 quad core processor, 2x2 gb G skill DDR2 800 Ram, Nvidia 6600 PCIe video card, Rosewill 850 watt power supply, phillips DVD burner, Seagate 500g hard drive, and an Antec 900 case.
I installed windows vista business 64 and everything worked fine, then i had to go so i shut my computer off, when i come back i got bsod. so i just restarted and everything worked again, so i updated my video driver and restarted. then i get bsod every time i tried to start normally so i started in safe mode with networking. it started but i found that like 3 of my drivers weren't detected anymore, 1 being my built in Ethernet card. unfortunately abit didn't include the ethernet driver on their cd but they didnt include the built in wifi driver, so i installed that and hooked it up. so it installed and i rebooted in safe mode with networking again, i went to download the bios update when i remembered i couldnt install them from windows so i made a boot disk and put the bios on another disk. i shut my system off and the bios update worked. but now, i got the bsod every time i tried to enter windows, and any mode, even after repairing it with the disk. but this time the blue screen doesnt even show on my screen for a second, it just flashes and it restarts. my brother came over and he said it was likely a memory problem with not having enough voltage going to all the memory, because i could get into the bios just fine. i would appreciate your help, and i will contact abit as soon as they open (on january 1st).