cpu fan running but no lights and want power up

Cleaned out my computer last night just takeing off the fans and blowing out the heat sink not removeing it and cleaned it up really good but now when i plug up the power to the back the cpu fan comes on but no lights when u push the power up button dont know what i did wrong have cleaned it out tons of time never had this problem so if anyone out there that can help my email adress is ellric1@yahoo.comn