Pc freezing without errors or bsod

[shaneo8712]

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.
specs:
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)

 

[monkeylove]

Please let us know what it says in the system event prior to the freezing problem.

 

[shaneo8712]

the last few events in the event viewer i can see are
kernel-general eventid 13
kernel-power eventid 109

those are followed by a lot of
service control manager eventid 7036

 

[monkeylove]

Have you tried the ff:

- chkdsk of the hard drives

- sfc /scannow:

How To Use SFC Scannow to Repair Windows System Files

- msconfig, disable startup and services to see if one of the programs or services started up is causing the problem.