Before BIOS boots OS, it should scan USB devices to find from what it can boot. Your hangup occurs on this step.

Thanks for the information about the PC booting up problem. I will try to remember and change the BIOS options so it doesn't try to boot from USB next time i switch the PC on.
It's not that big of a problem is the simple way around it is just don't have the Optimus Maximus plugged in during power up. I was just curious as to what might be the problem.

Thanks.