So I have this computer. It worked just fine for a while. But now it starts up, boots up into Windows just fine. After about 2 minutes or so, the computer will just randomly turn off.

The power light will start blinking, constantly, once a second or so. I hit the power button, nothing happens. I unplug the computer, plug it right back in, still the same problem.

If I unplug the power supply for 10+ seconds, then plug it back in, it will turn on, then immediately turn off even before posting. Light will be blinking blue.

If I leave it unplugged for like an hour, it will boot up into Windows... rinse repeat.

I tried chaning power supply, no good. I don't think it's a heat issue, because the system ran just fine for... a good few months with exactly the same stuff. Just as a precaution I did dust the whole case out, even though there wasn't much dust. Didn't help. I reapplied the HFS with arctic silver, no good. Not sure what the heck is going on. Any ideas?