MSI H81M P33 Motherboard Installation and Big Issues

Hello,

I mixed some old parts from my PC with new ones to make a new one (the old ones were working perfectly).

So I added new:

an MSI H81M P33 motherboard
a Corsair CX 430 power supply
a Kingston KVR16N11S8/4 4GB 1Rx8 512M x 64-Bit PC3-12800 CL11 240-Pin DIMM Value RAM DDR3 1600MHz
an Intel Pentium G3220 processor 2 cores 3.0 GHz Socket 1150 Box 3 G

AND after a big headache, I'm at the same point:

when I power it on, the CPU fan and the power supply fan start up before turning off within 5 seconds. The motherboard doesn't have time to do anything.

I tested the power supply with a paperclip, it works perfectly. I tried unplugging everything or each piece, it’s the same thing. From time to time, it attempts to restart once but the same happens again. As if there’s a loose connection somewhere...

I checked everything 5 times. It seems fine (but I’m blonde so you never know)... I also tried removing the battery, taking out the processor and blowing into it, changing the power cable, nothing worked!

Now I'm at a loss, so I'm taking all good ideas!!!

Here’s a not-so-great photo:


Thanks everyone for your help and Happy New Year!!!!!!