What connection are you using from PC to monitor?
Are you using a adaptor of some sort? DVI to Display Port or something similar. The adaptor may be faulty.
Or just try something different to your current connection if you can (depending on VGA and monitor ports of course.)
I assume you are running HDMI.... can you try the DVI port if your card and monitor support it?
Also try running the game as Admin for a laugh....sometime stranger things fix stupid problems.
Also don't know what gfx card you have but Nvidia GX2 cards have a dx10 fullscreen bug apparently
What happens when you hit Alt-Enter in windowed DX10 mode??