Everytime I try to overclock my Q6600 to 3.0ghz my computer will freeze or not get passed POST. If I try overclocking in windows it will just freeze and if I try it in the BIOS it wont go passed POST. Right now, the highest it'll go is 2.75Ghz. Please help me figure this out.

My setup is:
Asus P5NE-32 SLi
Q6600
EVGA 8800GTS 640mb in SLi
2gbs of Corsair DDR2 800
600W power supply

We need more info.

Is your RAM linked/unlinked to your FSB. I recommend unlinked, and then synced once your done your OC.

What are your voltages.

Have you locked the PCIe frequency to 100mhz? It should be.

Have you disabled Thermal Control and Halt State? These should be off.

Have you flashed to the most recent BIOS for your motherboard? Something you should do if none of the above fixes the problem. Be sure to google how to do it before you try.