PC Powers on but powers off immediately

[Continumm]

Hey guys, so I'm having some problems with my pc. I don't know what information is necessary to help troubleshoot so I'll just include what might be helpful.

 

To make the backstory short I was playing dead by daylight finished up a game and I was spectating my friend. Then my monitor goes black and shows a "no signal found". I thought it was my graphics card (radeon r9 280) not having a secure connection so as I'm making sure no cables fell out I smelled a faint scent of ozone. So i figured it was best to turn it off and let it cool (I don't overclock or anything like that. I have only messed around with the timings to get my newer ram stick on the same timings as my older ram sticks - 16gbs in total) After allowing it to cool for about 10 minutes I tried to boot it back up again after having turned it off and unplugging it. However, now the pc won't post. Like it will turn on (fans light up/ spin) for like half a second but then it turns off. I checked the power supply with the paperclip test and it can maintain fans (spinning and lights) while using a paper clip but whenever I plug it back into the 24 pin connector and try the power button it does the same thing.

 

Things I have tried - Resetting the cmos (though I don't know if it worked because the motherboard probably has power for less than a second) / removing the cmos battery / using the jumper pins to start the pc instead of the button / removing all unnecessary modules like my graphics card, hard drives, dvd player, etc. / removing all ram sticks / and checking the board for visible problems ie capacitors blown etc.

 

Currently I don't know what could be causing the problems. I'm not in anyway an expert with computers/diagnosing problems with computers. I just have intermediate knowledge of how computers function/ the parts that make the computer function. So as of right now my feeling of what could be the problems is maybe the cpu? I haven't messed around with it at all but maybe while playing the game it over heated and broke? Or maybe the motherboard is bad? Any help with troubleshooting my problem would be an amazing help. Also I don't know if it's worth mentioning but (stupid mistake i know) I had my desktop under my college bed which is elevated so It has air but there is the possibility for dust accumulation (4 fans blowing in my computer)

 

If anyone can help that would be hugely appreciated! Thank you.

[Anghammarad]

without knowing what is inside that open case, my tipp would be PSU fault

[Continumm]

3 hours ago, Anghammarad said:

without knowing what is inside that open case, my tipp would be PSU fault

But the PSU is able to run with a paper clip connected from ground to the black wire? Would the PSU be at fault or would it have caused damage to the motherboard? Also I don't remember all the specs associated with the desktop but I know the graphics card is a radeon r9 280 and the cpu has 6 cores (forgot the name and now I cant look it up without my pc being online) anyway the motherboard is an older model its a        ga-78lmt-usb3         and the PSU is a EVGA supernova NEX750B. other than that the cpu cooler seems to be from ZALMAN? Its a 2 ball-bearing cpu cooler. If you need anymore information I can provide it.

[Anghammarad]

Well that behavior I know from a lot of custom build work computers... they went to a on off loop... it was always the PSU in that cases.