Asus Z97C and Seasonic PSU Wont boot until unpluggin PSU

[elloco4ever4]

Hello everyone
Im having an issue with, I guess, is the motherboard and PSU.
I have an Asus z97 c, working for like 2 years now with no issues. I´ve changed the PSU a couple of weeks ago for a Seasonic 620 Bronze modular. Everything works fine, the thing is that when I shut down the PC, the next time I hit the power button the computer won´t start. When I hit the power button the lights go on, the fans turn on, but on the chasis (which has 2 lights: power light and hdd light) the hdd light only goes on, the power won´t. After that the buttons of the chasis wont respond and the BIOS beep wont be heard. The only solution is unplug the computer, and plug it on. After that, the computer will boot perfectly fine. This happens each time. What im doing till I find the solution is after shutting down the computer, turn the PSU off till I need it. If I do that the computer will boot perfectly each time.
I´ve checked and all the cables seem fine, I´ve checked the famous jumper of the ASUS motherboard and its perfectly in place too.
What could be happening here?
Thanks in advance

Spec:
i7 4700k (no OC)
8gb x 2 gskill DDR3
2 Hdd
1 sdd
Zotac GTX 660

 

[The Original Ralph]

on Seasonic's FAQ page they suggesting clearing CMOS when installing a new seasonic PSU

 

[elloco4ever4]

I´ve tryied to reset the CMOS but still the same problem

 

[karenjoly]

I suggest returning the new psu

 

[elloco4ever4]

I first wanted to try everything, since it does not seem a PSU problem. It works perfect once it booted up. I mean its working for hours and normally the computer is rendering or doing heavy tasks. Thats why I think that this should be some problem with a configuration or something. But thanks for the suggestion I´ll have to do that if I cant find anything

 

[karenjoly]

When the computer won´t start it does seem like a power issue. I had that problem with a very old unit and when I took out the power wires I found myself fortunate I hadn't burned the house down. You unit is new but has the same characteristics. If issue remains using a new unit, then you'll likely have to replace the board.