PSU Problem

Hey guys im getting a new PSU tomorrow and i took mine out already but i left some info on my pc that i need…i tried setting up my PSU again (Never Did anything before with the Power) it looked like evreything was setup but the power button on the front of my pc doesent work because when i flixk on the switch on the back of the psu evreything starts up for about a second then shutsdown(it normal,it does that when you flick on the switch) so i know i have evreything set up exept for the Power Button..any suggestions?