Had no trouble with my first one, so of course it had to be the second one 
If i turn on the power switch, the MoBo lights turn on, so it seems like the power supply works and electricity flows. But if I turn on the power button nothing happens. No sounds, no fans spinning.
I tried:
- unplugging 20+4 pin MoBo connector and 8 pin CPU connector and replugging them
- try to remove the pw switch connector in the jfp1 panel and starting it with a screwdriver
-removing RAM
Are there some other things I should look after? I'd appreciate if you'd mention easy to do things first, so that I don't have to screw off everything if the problem is pretty simple.
To be honest I COULD have damaged my CPU pins while mounting the stock cooler, but shouldnt the fans still work even if the CPU was broken?
Edit: http://prntscr.com/rac7f8 component list, working with stock amd ryzen cooler instead of the water cooler and the B450 is ryzen 3000 desktop ready
I got some loose cabel hanging around but I am pretty sure they aren't essential to powering the PC.
Edit 2: If you want any pictures just ask for them, I'll upload them on imgur.
Thanks.

If i turn on the power switch, the MoBo lights turn on, so it seems like the power supply works and electricity flows. But if I turn on the power button nothing happens. No sounds, no fans spinning.
I tried:
- unplugging 20+4 pin MoBo connector and 8 pin CPU connector and replugging them
- try to remove the pw switch connector in the jfp1 panel and starting it with a screwdriver
-removing RAM
Are there some other things I should look after? I'd appreciate if you'd mention easy to do things first, so that I don't have to screw off everything if the problem is pretty simple.
To be honest I COULD have damaged my CPU pins while mounting the stock cooler, but shouldnt the fans still work even if the CPU was broken?
Edit: http://prntscr.com/rac7f8 component list, working with stock amd ryzen cooler instead of the water cooler and the B450 is ryzen 3000 desktop ready
I got some loose cabel hanging around but I am pretty sure they aren't essential to powering the PC.
Edit 2: If you want any pictures just ask for them, I'll upload them on imgur.
Thanks.