Try updating drivers from amd's website using there automatic finder tool that you download. If it recognizes a card you are in good shape. If it doesn't (you could also download gpu-z) then come back on here and post because more than likely it is a physical problem.
Now just to make the obvious questions. Your display (monitor, tv, etc...) is plugged into the GRAPHICS card and not the place that you would have had it before having a dedicated gpu.
Did you plug in the power cables into the side of the gpu?