CPU Fan Error Press F1 to continue...

If you didn't plug the fan into the cpu fan header on the motherboard you will get this error. If you are using power directly from the PSU you should be able to disable the warning in the bios.

So i also have a Crosshair III with a Phenom II 965 and i replaced the stock heatsink with a scythe mugen rev B. Got the same error on the boot screen, searched the forums and it sounded like the mobo monitors the fan speed.

Because the mugen is a PWM fan, it can throttle itself back if you don't have it manually cranked to 100%. This can cause a low RPM warning (even though nothing is technically wrong).

So i went into my bios, set Monitor Fan Speed for the CPU fan to Ignore and problem solved.

Yep think that's the same way I solved my problem... BTW I am loving this rig playing Mass effect 2 is beautiful! Multi-tasking doesnt bog this system down either