No HD on HD ready TV. I recently bought this tv and cannot get it to work with my xbox 360 in HD

Question

I recently bought this tv and cannot get it to work with my xbox 360 in HD (using the Pb Pr and Y cables and connections on the back). I connect the cables correctly and nothing, the only time it works is in SD when I connect the composite cable and that sucks. The component cables are in properly, but no HD on any of the channels. Please help! The tv is a Bush LCD32TV24HD model.