dell optiplex 390 minitower

790, 390

Dell 5 pin power switch header on motherboard 

@redxps630​ I try to short this pins but no respond , orange led in motherboard is lighted up but fan spins don't turn or anything

replace cmos battery w new cr2032. Clear cmos settings via motherboard jumper 

if still not turning on, test 790 motherboard using a verified working 24/4 pin ATX psu.

@redxps630​ These are my atx pwer supply : both of them work propely with other pc ( i test them)

@redxps630​

But the hp atx works fine with this dell optiplex 390 i can short the pin and power up the pc but corsair one i can't do the same , i search that the max load wattage combined 3,3 v and 5 v must be above 150 w and in my corsair is 130 w as you can see in the picture, is that the problem ?

i clear the cmos and rplace the batteru but no result 

more likely this particular unit of Corsair is defective or failing, even though it works in another test pc.  You have proved that the 390 unit itself works fine.  When a psu is failing, it can still turn on some motherboard.  Different motherboard have different minimum requirements on the psu current and voltage.  Since your 390 works, but it rejects the Corsair, that is already proof that the Corsair is no good.

@redxps630​  i found this article in corsair community and has the same issue

at the end of day, your pc works but the corsair psu does not work with it, and you cannot change this situation because the psu is not servicable.  I suggest you move on to a different 750w psu such as EVGA or Dell and hope that would work.