!!!Drivers!!!, make sure you have the latest WHQL drivers from NVIDIA, as you are using Vista 64, it only works with tested and aproved drivers, i belive the latest ones are 174.74.- also you can use driver cleaner so all of the remaining files of the previous installation are delete!
There's nothing wrong with your card or your monitor. You have to set the card up to see the montor as a "tv". I don't have the right machine running right now to tell you how to do it, but a phone call to nvidia will have you up and running in minutes. Good luck and tell us how it goes.