[ziggytrix]

Have you checked your video card manufacturer's website for known issues? It sounds like this issue is specific to either your video card or dual monitor setups.

I'd also try it with the PC freshly rebooted with the monitor cable completely disconnected - I seem to recall having a bitch of a time getting WoW to run with two monitors on my old NVIDIA card. I could be misremembering, but I think it wouldn't run correctly even with the 2nd monitor plugged in, but disabled.