PC sometimes won't turn on until I unplug it from the wall for a 30 seconds or so. Faulty PSU?

Just like in the title my PC has an issue when it won't turn on. Power button does nothing, fans do not spin, PC is completely dead. First time it happened was when I put it to sleep, sometimes it wouldn't wake up so I just avoided putting it to sleep as a temporary solution that become quite permanent... Simple power off worked...