Blank screen after hooking up new PSU

[cashblingbling]

i just put in a new PSU and turned the PC on, it came ON just fine the fans were spinning , but the screen just stays blank , my motherboard has a 24 pin connector , and the PSU has a 20 pin connector, but it worked just fine with my old PSU it had a 20 pin connector and 4 were left out and it still worked fine , so can somebody please help me out ....Thanks

 

[raybay]

Suggest you install a 24 pin power supply. Those extra four pins are the key to video graphics on some boards...
Does your video graphics card have its own power socket on the back end?

 

[cashblingbling]

i just use the onboard graphics , but the power supply that came with this pc used the same 20 pin connector and 4 pins werent connected and it worked great , but wont work with this PSU