Try changing rendering systems. It could very well be a graphics card issue like Fireboss has mentioned, so do give that a look to see what sort of graphics card ye 'ave installed.
I'd also check the resolution settings of y'er game. I'm pretty sure ye can do that in the white box that pops up when ye open the game after a crash or open a second tab of the running game. Ye may need to fiddle with the resolution to see what works best with y'er computer.
One last idea, and this one is just a shot in the dark. Try running the game as administrator. I've known this to fix a lot of weird issues so perhaps this might do the trick if nothing else does.