Vista - Changed Power Options now computer will not wake up.

I wanted to make the Shut down in Vista the same as XP and went to Power
Options,then Power Buttons and Lid, then Start Menu Power Button, then Sleep
and in drop down clicked Shut Down then OK. The Start Button changed and
when it was clicked the computer shut down. When I went to re-start the
computer it is just blank. Nothing is happening, even the mouse and keyboard
do nothing - dont even light up.