try to run the x server at 60hz (refresh rate)
Did you try to run X with the framebuffer module? you wont get any acceleration but with this module all cards should run so if you still get those line maybe your card is damage.
The thing is that you get those lines in the console too so it looks like this is something worst than a driver issue.
Signatures are a waste of bandwidth!
thanks rwolf!!!!! :-P