Hi kotumaru,
First of all does a different graphics adaptor work?
If it does then you can pretty much rule out a faulty connector on your mobo.
If not then try a new mobo and see if that works.

If you have ruled out a mobo fault then the fault will probably lie with your gfx adaptor. Try a new card the same as yours if possible.

Is your gfx card still under warranty?

Try these and let us know how u get on.