It's not quite as simple as it appears - the graphics card clearly is working, or you wouldn't have a useable display on your screen - and clearly you have.
What exactly does it say for the display card in Device manager? - maybe the correct drivers are not loaded for some reason.
How does your screen look? - this may give a clue as to what's wrong.
Has it been like this from the forst moment you switched on? - if is has, the responsibility is with Simply, but it may be easier to recify yourself if it's only a driver issue.