Help with powering up pc

Hello,

I took my fan out of my PC to blow off the dust ( my computer would keep shutting down). After cleaning ithe fan and reinstalling it I went to start up the pc. When I pushed the on button no LED came on but the fans turned on, nothing came up on the display either. When I went to turn the pc off it wouldn't turn off. I had to unplug the main power cable from the pc. Did I cause this when I cleaned the fans? Nothing came unplugged.