Need help with Steam(Magicka), for a friend.

[KentaRawr!]

A friend of mine and I want to play Magicka together, but she's experiencing some problems. When she tries to load the game through Steam, the screen goes black temporarily, and then just goes back to her desktop. We've checked a few things, but I'm honestly bad with computers, and neither is she. When it comes to PC games, would you guys know what might cause something like this so we can narrow it down?

Edit: Nevermiiiiind. It was her video card.