I bought a used Asus G1S-B2 laptop off of ebay for repair/parts. It has the common Nvidia GeForce 8600m GT error, where there are green vertical lines across the screen. I have gotten it to start 3 times, which I used to install all of my standard programs and all of the updated drivers (including the latest graphics one), and it was working fine until I turned it off yesterday. I even got on the internet, facebook, and played some java/flash games with no problem. I waited til today to try to use it, and now it's gone back to the same issue. Do I need to replace the graphics card or what?