On my custom rig, I have Windows 7 as my primary OS. I'm looking to do a secondary installation of Ubuntu 13.10 on the system. I have Ubuntu ready to install on a USB disk. I just need to set the USB as my primary boot device. When I tap F12 at bootup to edit my device sequence, it locks up and I'm unable to use the arrow keys. I'm aware that tapping the F12 key too many times has a chance of filling up the keyboard cache and locking up the keyboard. However, I tap the F12 key less than 10 times. Any suggestions?