I have an old duel pentium III computer (2x1ghz) with a geforce 6600. I install windows 7 on it and it works great except when I go to install the graphics drivers. I installed the windows 7 driver and upon reboot it loaded the login window fine, but after entering the password, all I see is a black screen and eventually it blue screens. But if I boot into safe mode so without the driver it works fine. I then tried a geforce 5400 fx with windows 7 driver and the same thing happened. sounds like a motherboard issue but I have no idea. (I also reinstalled windows 7 and same problem)
Microsoft does have an official Windows 7 Support Forum located here http://tinyurl.com/9fhdl5 . It is supported by product specialists as well as engineers and support teams. You may want to check the threads available there for additional assistance and feedback.