I would assume this is the problem. I recently had a similar issue. After doing a fresh install of Windows 7, everything worked find until I installed the graphics driver, and then after the windows loading screen it just went to a black screen. After trying a whole bunch of different graphics drivers, I finally figured it out. I still had both my DVI monitor and my TV (via HDMI) plugged into my card. I unplugged them both and plugged just the DVI back in and there was the log in screen. If I were you, I would try to find a friend who will end you a monitor for an hour and try that. If it works, set up your TV as your default monitor, unplug the monitor, reboot and see if it works.