My pc was starting to go on the fritz, so after some hard drive issues I decided to install a new internal drive. After a few good days my computer started to freeze an have thin black and white horizontal lines cross the screen. This didn't happen during anything graphics-intesive, which makes me think its not a video issue. After a reboot all was fine for a bit, and then it did it again. Now it's happening before windows even gets started. Any ideas?
Sounds more like a bad display or video card. See if the problem shows up on an external monitor -- if it doesn't, it's likely a bad display. If it does, boot in safe mode -- if the image is OK there, it's likely a bad video card.