Just received my 27" iMac i7. I've noticed that every few hours I need to lift the screen up, because the weight of the screen pulls it downward on it's hinge.
Does anyone else have this issue? What do I do to resolve it?
In the hours my iMac (i7 with broken screen or video card...) stood on my desk it was rock-solid.
It should not need to be adjusted so maybe the spring in your's is broken...