Power button not turning on unit following HD replacement

I replaced my 250GB hard drive on my 2 year old MacBook Pro 15". While replacing it, the orange ribbon cable connecting the keyboard and logic board came loose and I brought it to the apple genius bar to seek help. They showed me with reluctance where it plugs in and thought it'd be fine. Now pressing the power button yields nothing. The unit's battery has a charge and the green light comes on to show the battery is charging. Any help on why the power button yields no power/reaction? Thanks. :)