PC dual booting & resetting bios/OC CPU when external HDD is in USB

[fakeblood]

First of all I apologize if this is in the wrong section as it involves a couple of different subjects. This is probably something very simple but I can't figure it out and it's bothering me.

Motherboard: GA-EP35-DS3L
CPU: E8400
Western Digital external HDD (USB 2.0)

The E8400 has long been OC successfully, ran Prime95 and other tests on it so it's completely stable. The issue occurs when I boot my PC up with the external HDD plugged into the USB -- it boots, shuts down, boots again and sets the CPU back to 3 GHZ in the bios.

I'm sure I will feel really stupid after hearing the fix but I'd like to be able to just leave it plugged in. Thanks for your help.

 

[rexter]

Check the bios for primary boot device, use CD/DVD drive as your primary then hard drive, disable others. If you have USB keyboard, try pluging that in to the 1st USB port. If that doesn't work, try setting the bios to default or safe mode then adjust the setting one at a time.