Hello, Go to this link here:http://www.geforce.com/drivers then click "Auto detect you GPU" and it should run a scan on your system for NVIDIA products. Note that it will ask for you to run a simple plug in to check it. No virus will be involved in the process. So Virus free
sorry they dont even make one for vista, you could try to download the xp one and install via compatibility mode (save driver to desktop right click and select trouble shoot compatiblity) but it may just give you a bunch of problems.
Usually when you load a new OS and you don't have the drivers disk for the hardware then Windows has a generic driver that will allow the device to work but not at full capacity like the specialized drivers for the device would. Nvidia makes thier drivers universal so that you have the same drivers for all of the video cards but it will only be for a limited amount and not all the way back to the begining.