PC does not power on

My PC in the living room does not power on in the morning after I hibernated it the night before. The same happens too when I shut down the system. No sign of life at all when I hit the power button in the morning. The odd thing is that when this happens and I move the PC to the bedroom, it will start up and boot without any issues and it will work fine the whole day and night. And if I succeed in getting to power on and boot in the bedroom and then move it back to the living room, it may power on from there if I am lucky. If it doesn't, I would use the end of a USB extension cord and "play" it at one the USB ports, by gently inserting it in and pulling it out and repeating this until the PC suddenly powers on. I would have to press and hold down the power button at the same time while doing this odd ritual. It would power on most of the time when i do this.

Most of the time this works when I shift it back to the living room after I succeed in getting it to start up in the bedroom. If it doesn't, I would shift the PC back to the bedroom and get it to start up again. Lately, it won't even power on in the bedroom unless I also try to insert a USB extension and perform the same ritual at one of the ports. This is getting annoying and tiresome, however.

Could someone please tell me what's going on. Is the power supply unit failing and I have to replace it ... what? I would appreciate some input on this/ Sad to say, I am not tech-savvy beyond changing the CMOS battery.