It's probably worth mentioning that if this were something that happens to a lot of people, regularly, month after month, all year, Microsoft would be aware of it and would have done something about it. There should at least be some information out there. But all I can turn up in Googling is some links to various matching keywords such as how to roll back a driver, and how to do windows updates, plus a few people complaining about Vista installing its own drivers for their Nvidia onboard graphics, asking how to install the official ones from Nvidia.