Computer runs but non of the peripherals work

[Prefix 895]

I just put in a new cpu fan and two other fans. All the fans turn on and all the lights on the gpu but the mouse and keyboard don't light up and the monitor says no signal

 

[CoolDude X]

I Think Your Motherboard's Power Cable Is Not Properly Connected,Check All Cables(including USB,SATA,POWER etc.)And Re-Connect Them And Also Check Your VGA/DVI/HDMI Cable