Question PC getting no display randomly

[Ziio]

Hello everyone, i am sure my case will intrigue you all, for me at least is the weirdest issue i ever had so lets get started.
Summer 2016 i built my custom pc AMD FX 8350
Ram Corsair ddr3 2x4gb 3200
PSU Corsair 550w
AMD Saphire r7
Motherboard MSI 970A G43
HDD WD 7.2k rpm blue
Built it myself everything worked fine for 2+ years.
Sometime in 2017 i am sure i messed up cause i connected a usb in a port and the cables touched, screen flickered but everything still run fine.
November 2018. Went to 1 week vacation and turned off PSU switch.
Came back booted pc and everything was working except i had no display and GPU fan was no spinning, keyboard had power because of leds but mouse didnt(mouse normally gets light after POST unlike keyboard) all other fans spin, leds working, hdd working . Did everything in my power back then but couldnt get it to work, tested another PSU AND GPU still nothing, tested my GPU on a friend's PC, wasnt working there so i thought GPU is the problem . September 2019 i buy a new GPU AMD saphire RX 570, plug it in but fan spins for a moment and then it stops still no display , followed a guide online and cleared CMOS with jumper, success! PC works fine.
January 2020, we get a blackout and same problem as in 2018, again i unplug everything and clear CMOS, PC works again this time but forever after that i get no display on first time i turn pc on, i always have to reset it to get display , 1 week ago we get 1 more blackout , this time everything works fine . Yesterday morning i clean my tower of dust as i ve done 100 times before, i only removed ram during the cleaning and after i was done PC worked great for all day. Today morning i turn pc on, no display and no GPU fan spinning exactly as the other 2 times before, i try to clear CMOS but this time it doesnt work, i write this from my cell phone. I am 95% sure its the motherboard but since ryzen are out now i cant just replace MB, its better if i build a new pc. As of today my friend got my old GPU to work on a backup pc he has so my GPU wasnt the problem back then. I removed HDD and RAM to see if the motherboard beeps but it doesnt(yes i have a speaker on and it worked fine before in cases RAM wasnt correctly in place. Any thoughts on the issue?

 

[Ralston18]

That 4 year old PSU would be my first suspect. Especially if the PSU has been subject to power blackout/surge problems and/or heavy gaming/computing use requiring constant high power demands.

Since there have been successful boots look in Reliability History and Event Viewer for error codes and warnings that you can correlate with the failures.

Some constant error may help identify the root cause.

Or, just overall, if you see a wide range of varying errors and problems that would be indicative of a failing PSU.

Another thought:

Are you using any surge protectors or power bars between home electrical outlet and pc? If so, try booting without them to determine (as a matter of elimination) if the pc boot failures, etc. end or continue. Try other electrical outlets as well. Both on and off the current electrical circuit.

 

[Ziio]

Thank you for the fast response.
Sadly as i dont have display and not another way to view the errors if there are any.
The psu is indeed a thing i had in mind but i tested another psu when the problem first occured and it didnt make a difference, i indeed have a surge protector and i tried another outlet today without it but sadly the problem persists, no display and the GPU fan isnt spinning.
If this helps the error i was getting after reseting my PC (because as i told you i got no display the first time i switched it on after 2018) was Default Radeon WattMan settings has been restored due to unexpected system failure