I have 2 monitors, a Belinea 19" widescreen as my main and a AOC 17" as a secondary.
Unplugged the 17" earlier and bam! Pc booted up to ABIT logo screen and nowt on the 19"
I could get into bios easily enough. As soon as i plugged in the 17" both work.
I'm probably missing something really simple aren't ?