|I doubt that it is your graphics card.|
I have seen this kind of problem many times on laptop TFT monitors. Usually the problem turns out to be the display itself which you can only fix by replacing it.
You also often find that pressing on certain parts of the TFT screen edges can cause these lines to disappear or in fact more of them to appear.
I would therefore agree with override and try a different monitor first.
☺ When everything else fails, read the instructions.