Nvidia GeForce 8600M GT

I just bought an Asus G1S-B2 off of eBay, for repair. The guy said that he had it checked out, and that it had the common issue of this graphics card. When I try to start it up, the screen does the Asus Gaming Series animation, but in the background there are either green vertical lines or red blocks. When it trys to start windows (it runs on Windows Vista), there are white dots across the screen, and the Windows Logo is not there. After it tries to start Windows, it shuts down, and retries the process. I have gotten it to start normally twice, and then I installed all of the drivers from the disk that came with it. I don't know if I need to update the graphics driver, or what because I just talked to an expert and he said before you replace it you should update the driver and see if that helps. The only problem is that I don't know how to get the driver from me other computer to the laptop that won't start windows so I can't get the driver on it. Any advice? I'm desperate!