hmmm... Check the manual that came with your mobo. See if it has the max capacity labeled for each ram slot. If it is less than 1 GB, then that is at least one problem. For the games crashing, it COULD be related to that, but it is probably something else.
Maybe your video card is overheating? Do you notice any artifacting before the freeze?
Intel Conroe e6750
SLI EVGA 8800gts KO's
4GB Patriot DDR2 800mhz
22" Widescreen Sceptre LCD monitor 5ms
OCZ 700W psu
320gb seagate w/ perpindicular tech.
Creative SB X-Fi Fatality
Thermaltake Armor: Extreme Edition