I picked up a 2007 MacBook (2.0 GHz C2D) at the computer recycler. It was listed as untested and didn't have a hard drive. I got it home, plugged it in, and it did boot up, but there were lines running vertically down the screen, and every time you moved the screen, they would change. You can position the screen in a way so it disappears. I installed a hard drive that had an installation of Snow Leopard, and everything else seemed to work just fine. It looks like someone attempted to repair the laptop at some point before, as there were a few very loose screws in the battery compartment. Anyone know what the problem could be, or how difficult this might be to repair? Thanks!