My (HDMI-IN) input is not working.  im trying to play my Xbox360 on my Alienware 17 display and it say it can.  i have went on YouTube and saw other people playing on there screens i don't know how to use my screen. i mean i know how to turn it on step by step. Please help!
1.turn on xbox plug everything in
2.plug it in the ALienware 17 (HDMI-IN) input and i pressed the button on the keyboard to
3.nothing happens and when i press the button it says "please connect (HDMI-IN) device"