I've been having some odd issues with my PC over the past bit and haven't been able to find a solution. At this point I assume its the PSU but thought I would ask.
To get my computer to boot, I have to turn the PSU off in the back of the pc, turn it back on, then hit the power button in the front after 5 seconds. Usually this will boot the PC, but as of late it has taken a few too many tries.
If the PC doesn't boot, the blue LED on the PSU will blink and look like it's struggling to turn on, I assume it is the PSU as I have replaced the processor, ram and video card through normal upgrades over the past couple of months, and this has had no effect.
It definitely sounds like a PSU issue. Its possible that you are overloading your PSU or it may just be faulty. Either way you'll likely need a new one so if you post your full system specs we can recommend one suitable for your needs.