Xbox 360 green light turns on but it does not work or boot up

When I turn on my xbox 360 I can hear the fan working and The green light in the middle turns on. I am not able to connect a controller. When I turn on my tv nothing shows up. My xbox had been working perfectly fine a couple of minutes ago. When I tried to turn it on again this happened. The adapter light is orange when the xbox is off and when I turn the Xbox on it turns green. I am able to open and close the disc tray to insert a game disk but nothing happens. Does any one know what the problem is?

I guess you have to get yourself a new xbox or send it to Microsoft if you still have warranty (if you have something like x360key, obivously remove it first). It has nothing to do with the HDMI cable (or any other cable) since you can't connect an controller (you could try another controller).