Warcraft 3 problem

Im pretty new here but have been searching this board for about a month now.

I’ve encountered a problem that is getting on my nerves. I have a real warcraft 3 roc and everything works fine until i actually get into a story mode game or campaign. The screen becomes pretty much completely balck. only some of the characters or buildings can be seen. Im pretty sure its not the computer screen because when i search in the black area and click on an orc or human etc the little face down the bottom is mental, some of its missing and all sorts of stuff.
If any body has any clue what im talking about please help me thanks.

Try reinstalling the game, reinstalling the graphic card drivers, reinstalling DirectX or upgrading to the current version.

Also, try changing some settings (maybe change the graphic buffer, or lower the quality – try all different combinations)

I was just wondering how to change the graphic card settings?