Client Black Screen

Recently got a new computer and most of my games are running fine, however WoW is currently having some problems for me. I am running the wotlk old client without the WoD models. When I start up the game all I see is a black screen but I can hear the arthas start up theme followed by the music on the login screen.

I'm not too great with computers so I'm not all that sure what the problem could be. Just checked my drivers and they are up to date so that shouldnt be the issue.

Any ideas? thanks