So my pc has been randomly freezing and locking up after an hour or two of use and i cant figure out why. I have updated my graphics card and bios. I have tried both ram sticks in individually into the first slot, so unless both ram sticks went bad at the exact same time, they should be ok. I did try to run memtest overnight, but upon waking i found that the pc had restarted. I have cleaned out the pc of dust, and the heat seems fine on cpu, gpu, and mobo. I have run a full av scan with malware bytes and cleared up registry and temp files with ccleaner. I dont really know what else to try at this point, any help would be great.
windows 7 professional 64 bit
intel i5-2500k cpu @ 3.3ghz
2 4gb sticks corsair vengeance ddr3 ram
p8p67 pro rev 3.1 asus motherboard
2 nvidia 560 ti's in SLI
Crucial M4 CT064M4SSD2 2.5" 64GB SATA III MLC Internal Solid State Drive (SSD)