Power come on, no beeping or display

My computer was bumped and all a sudden the monitor had a messing display and nothing worked (pressing buttons on keyboard, moving mouse). So when I powered off and restarted the computer don't happened. I could tell nothing was going to work because I did not hear no beeping when the computer came on, thus no display on the monitor. Up to this point, everything was working fine.
I unplugged all the cables, tried to disconnect some cables inside the desktop and plug back in. The fans are working. Still nothing ...
Any idea what's wrong???