computer wont boot with eatx cmos 12v plugged in

Hello all

Here my problem, yesterday, my computer went black, tried to reboot, noticed activity for 1 sec, then shut down again.

did some test with another psu, same result. tested my psu in another computer and it worked.

when my plug for the eatx clr-cmos 12v (2x4) was not plugged in, all the fans, lights and normal computer activity seem to work. (tested for 10 sec max, cause i didnt want to burn something in there... (yea im pretty novice, i dont even know what that plug is for)).

Here my computer spec.

MOBO : Asus crosshair IV formula
CPU : AMD phenom II x6 1090t
Ram : 16g (4x4) Kingston Hper-x
PSU : CM Silent PRO 850W
HDD : 2x 500g black caviar WD + 1x green 1T WD
GPU : Asus Radeon HD 6950

hope im not forgetting anything...

thx for your time and help.