PC won't start after sudden standby while gaming

[gokussj1998]

When I was gaming my pc suddenly switched to standby mode. When this happened I tried to restart the pc, but with no success. Now my pc won't even start up. I have tested different possible problems.
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I have tried the following:

• 
  ■ Test if it is a PSU problem. To test this i tried the paperclip method. The result: PSU fan started
  spinning continously.
  ■ Test if it is a motherboard issue. To check this problem I replaced my motherboard. the results
  were odd. So with the motherboard I used before replacement the pc started for like 1 sec
  and then switched off.
  With the new motherboard however, the pc turns on(all fans start spinning and hard drive spins) but it won't display anything on the monitor,
  so a black screen. I also can't power off the pc using the power button(but i can turn it on with
  power button).
  ■ Test if it was a cpu related issue. To check this, I replaced my cpu with an old AM3 CPU(in the
  new, replaced motherboard). I got the same results mentioned above. Bc of the result I don't
  think it's a cpu related issue

The parts I used for replacing were spare parts I had laying around, so I didn't buy new ones.

Spec list with and without replacements:

• 
  PSU Coolermaster GX-450W Bronze
  CPU AMD fx-6350
  GPU Asus Geforce GTX1050Ti Ceberus
  MOBO MSI 970A sli krait edition
  RAM Kingston HyperX 4 GB 1600mhz 2x
  HDD WD 500GB 7200rpm
  SSD Intel 50 GB
  FANS 3 NZXT case fans
  CASE Sharkoon VS4-W

(replacement parts):

• 
  CPU AMD Athlon X4 630
  MOBO AsRock 970 Extreme 3
  All the remaining parts are the same as above

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Does anyone know what the problem might be? I am thinking about buying a new PSU and see if that solves the problem, since it is the only part I haven't replaced.

Thanks in advance.

 

[CustomBulids]

When you press to power up your PC, do any lights or fan move to indicate that you are receiving any power at all?

 

[gokussj1998]

When you press to power up your PC, do any lights or fan move to indicate that you are receiving any power at all?

Yes, when I turn on my pc all fans start spinning, but I nothing displays on monitor. This is after I replaced the motherboard with the AsRock 970 Extreme 3. Before, the fans only turned on for 1 sec and pc shut down(MSI 970A).

thank you for your reply!