When i shutdown my PC. I have to leave my PC unplugged for several hours for it to boot up again successfully, usually when I try to start it the gpu, PSU and cpu fans will spin but there's is no HDD activity, signal, case fan or USB power. I noticed my CPU temps were around 50 degrees Celsius while idle although I was wondering if it could be a PSU problem. I have tried the paperclip test with my PSU and the PSU came on fine.