i have a lepa n500 power supply and my computer will not power up with the 4 pin cpu cord

[thawon]

I have recentely changed cases and now when i try to.turn on my computer with the cpu 4pin attached it will not power on at all i dc it and fan turns on and everthing has power not sure what the problem is and why it wont turn on

 

[thawon]

I have a amd phenon 2 quad core. Asrock motherboard. 8gb ram and 1t hd