boot selection trouble

i have an external cd drive and im trying to put linux on my acer aspire one a110, but everytimei hit f12 at the boot screen, the screen comes up that says "entering boot device selection menu..." but freezes there.

it only freezes when i have the cd drive plugged in. any idea on what could be causing this?
please get back asap, i dont like having a tiny version of xp on my laptop anymore.

 

nevermind. its working now. for informtion purposes for other peopl having trouble.

if this is happening to you, try switching to the usb post on the right side, the one closest to the battery thats the only one that it worked with.