Computer HDMI cable isn't connecting to my TV?

I've had my laptop computer (running Vista) connected to my HDTV using an HDMI cable for some time now to watch movies and such on my TV. It's worked great for the last month until all of a sudden yesterday I go to use it and the computer isn't transmitting the video and audio signal to the TV anymore. It still makes the *ding* noise when I connect and disconnect the cable, but the tv just says "retrieving data" and instead of bringing up my desktop on the TV it just has a blue screen that says "No signal". I can set up the TV to function as a second monitor ( as an extension of my desktop, so the HDMI cable and TV are working right), but I can no longer get my TV to display exactly what's on my laptop screen. I tried uninstalling and reinstalling my video driver on my laptop but that hasn't done anything either. How can I fix this?