Try the new catalyst 14.1 beta driver and see if that helps. I stuck a couple of those DVI->vga adapters in my cards and get better stability. I don't go the full route of sticking resistors and crap in there but it seems to work. Good luck I have had the same problems.
I have tried 14.1 beta and ended up reverting to the last final driver because I thought that might have been the issue. 14.1 beta gives me the same problems. Unfortunately I can't physically get to the machine right now, but I will definitely try a DVI->VGA adapter when I get a chance.