Question MoBo does not turn on unless the ATX green wire is jumped and PC is on standby mode for 5 minutes before turning on

Aug 15, 2022
Hi. My brother's PC is not turning on without the ATX green wire and the black wire jumped by a paperclip and having the PC be on standby mode (plugged in with ATX power on but not the PC case) for 5 minutes before turning on the PC. The PC unit is almost new except for the GPU which I think was the culprit.

For background, the PC was running fine until one day it didn't boot up. I tried plugging and unplugging all components but still, it didn't help. We brought it to a computer repair shop and they said the motherboard needed to be replaced. I replaced the MoBo, CPU, ATX power supply, PC case power and reset switches, and RAM, and I even bought a new SSD to be used and formatted the HDD. It worked for 3 weeks then stopped working again. I also tried discharging the MoBo (holding the power button on for 60sec while ATX is unplugged).

Now, turning on the PC needs a paper clip jumped to the ATX green and black wire, letting the fans spin for 5 mins, before switching the PC case on. But its life is getting shorter every time before it turns off (now only an average of 30 mins).

Do I need to replace the MoBo again?