Xbox 360 - no sound / video but rf light comes on

[stuntpenguin007]

Today I went to turn on my 360 and it wouldn't boot. When I press the power button on the console, the middle green light comes on, but nothing happens. The lights don't spin around in a circle like they normally do. I rarely play xbox, so the last time I used it was about 2 weeks ago, and it seemed to work just fine. The light on the power brick turns green when I press the power button.

What can I do to fix this?

edit: Got it working. I had to plug the system in with component cables, install a system update, and then plug the HDMi back in.