New build- power supply won't work

Acidbath

Honorable
Oct 31, 2013
15
0
10,510
Hey it's my first build (I have read all the instructions on where everything needs to be plugged in and I'm pretty sure everything is where it needs to go) and I'm having trouble with my power supply. First after plugging everything in, I was plugging the power supply's 24 pin in and it wouldn't fit snug or lock. So that worried me so after I plugged the GPU and and other bother things into the power supply I turned it on and it won't run it won't even cut on. I unplugged everything and tested the power supply with the paper clip method it runs when nothing is plugged into it. So I try plugging the The power supply back in and it won't work. I'm unsure of what's going on I've made sure everything is right with it. But it just won't turn on.

Any help would be great.

Thanks,
Nathan

EDIT :
Parts list :
MSI z77a-g45 (motherboard)
Corsair cx750m (psu)
Gskill ripjaws 2 x 4gb
Intel i7 (from my alienware x51)
Evga gtx 660
1t hard drive (from my alienware x51)
Lg disc drive


 

Acidbath

Honorable
Oct 31, 2013
15
0
10,510
Oh sorry forgot about that.

Parts list :
MSI z77a-g45 (motherboard)
Corsair cx750m (psu)
Gskill ripjaws 2 x 4gb
Intel i7 (from my alienware x51)
Evga gtx 660
1t hard drive (from my alienware x51)
Lg disc drive


 

Acidbath

Honorable
Oct 31, 2013
15
0
10,510


Yea I have plugged it in too. I think the 24 pin is in there good it just doesn't latch I see no gap in between the cable and connector