my hdmi cable worked fine with 1080p resolution, then a couple of days later i pulled the power cord and hdmi lead out to disconnect the xbox, when i connected it back up it didnt work and i have no idea why . i have tried checking the lead is in properly, and tried resetting display settings by holding Y and pulling the right trigger when starting the console up. does any1 know the problem??

Did you accidentally break the Hdmi port on the tv? Try replacing the wire. Unplug the AC cord to the tv and xbox for 10 min or so. Try another xbox if available. If all else fails, try getting service for your television.