A while ago, my PC started to take a while to turn on, as in I had to turn the power on from the plug and wait a few seconds for the power button to actually work. After a while this 'lag' time took longer and longer and now I sometimes have to wait hours before turning my PC on but sometimes it doesn't turn on at all and I have to leave it for a day or two. When I turn the plug on, I see a blinking green light on the back of my PSU but the fan isn't turning. From the sound of things, am I right in thinking that this is a PSU problem and I can fix it by simply replacing the PSU?