Want to type this quickly, don't know how much time I have.
Woke up today to find my computer on it's screensaver. Odd, I thought, as it's only on in logon screen. Sure enough, that's what it was. Logged on, proceeded to start surfing as usual.
I have an Asus board, and I run the Asus board monitor tool. It pops up telling me that my CPU fan is not spinning. I look and sure enough, it's not.
I fight with it for a while, thought it was the fan (replaced). It wasn't. Something wrong with the power header. Plugged it into the unused chassis plug, and off it runs. No issues.
Leave for work, come home. Wife says the computer has been shutting down all day.
I say okay, leave it be, I'll check it later.
It's now later. Had it shut down a few times. Reseat some things. Seems to be doing better. Then the problems start. It starts freaking out on me. Finally reboots, and the monitor (which states it's mode onscreen when it changes modes) says 'Monitor Out Of Sync' (which I've NEVER seen before on this monitor).
Crap, crap crap...shut it down. Unplug everything. Tear it all down.
Go to unplug the ATX power cable...hm...little snug there...
Oh, that's why...it's just a little bit melty on the +5V. Half of the plastic surround is still in the pins.