I have an Xbox 360-S. The green light comes on but that is it. It won't do anything. What do I do? I have tried to restart; taking it apart; but still nothing.
Try checking the HDMI cable, if it has been removed or it just moved and now is not plugged in correctly, then only the green lights turn on, but the system won't load.
Also, if it has been modified (RGH/JTAG), sometimes You have to wait longer for the system to load (up to 5 minutes).
If it has taken some damage (fallen off somewhere, got kicked over, etc.), You should take it for a repair.