Sounds like a problem with your grapic card or your monitor connection. See at the back of your computer if you monitor ( the one with the blue male part) is properly inserted. If it's alright at the back, see if it's properly in it's socket on your monitor itself.
If that doesn't work maybe its broken.
Of course it could also be a software problem, but I don't think so. go and see if you have all the proper directx downloaded and installed.
If you have this problem with more than just CA let a pro look at your card/monitor