PC not turning on with new PSU

[Coedgy]

So I bought an used PC, replaced RAM and GPU, bought new PSU to get GPU working (didnt have 6+2pin). I connected everything correctly and press turn on button and.... cpu fan and case fan works for 10 secs and shuts off, and nothing shows up in screen. Tested everything with old parts BUT the psu... doesnt work.
But then I changed back to old PSU (so the pc is now what it was like before) and it turns on. Soo.. its the PSU thats the problem?

PSU: Corsair VS350 (old one was some 300W poop)
GPU: Gtx 760Ti
MoBo: m2n68-la

 

[Dark Lord of Tech]

Try clearing the CMOS and then boot.

 

[Coedgy]

Try clearing the CMOS and then boot.

Uhh.. How do I do that 😀

 

[Dark Lord of Tech]

Take out the battery for a minute , put it back in and try a boot , sometimes helps with a new PSU being installed.

 

[smorizio]

hp and dells are picky with video cards if you dont have the newest bios on the mb. check that you do then see if the mb will post.

 

[Coedgy]

Take out the battery for a minute , put it back in and try a boot , sometimes helps with a new PSU being installed.

Did not work, same problem.

 

[Coedgy]

hp and dells are picky with video cards if you dont have the newest bios on the mb. check that you do then see if the mb will post.

I have no idea what bios does it have, nor how to install new one, I can change all the parts back to working state if its necessary...

 

[Coedgy]

hp and dells are picky with video cards if you dont have the newest bios on the mb. check that you do then see if the mb will post.

I tried with only PSU changed and it turns out it doesnt still turn on so i think its not GPU its PSU