Pc not posting PLEASE HELP

A few months ago I had sum problems with my pc not booting i guess my dad had fixed it for me and i never new fast forward 3 months i got bored and decided to take it apart and rebuild because i figured it was still broken got it all put back together all the ports are secure cpu is properly placed with no damaged pins and psu is working but for some reason my mother board is only getting power to the accesory light covering the I/O ports nothing else fans arent turning on no beep codes no motherboard code lights pressing the power button does nothing shorting the power switch does nothing there is a vbus pin broke off on the usb 3.0 header but i figure since it can run without that plugged in it should be fine with it broken?