As you can tell from the topic, my computer is a pretty ancient piece of junk. But it's been holding up pretty well - Fallout New Vegas and Crysis bow to my will! Until today. During the night, my computer rebooted or shutdown twice; I only found out about one because it woke me up with the PC Speaker droning. It was complaining about the floppy drive being missing, as apparently its CMOS settings had been lost (floppy drive setting reset, showing startup graphic instead of POST, etc). Turned off the floppy drive check, let it start back up, went back to sleep. Found out it had rebooted again in the middle of the night because something I'd started wasn't running anymore. Wasn't too worried; this is like a 4 year old motherboard, wouldn't surprise me if the battery is weak. Messed around with FNV for an hour or so (this is important), decided to go into my BIOS to put the settings back the way I liked them before getting too involved. First thing that scared me was when I went into PC Health and saw the CPU sitting at a nice warm 125 C. "That's not cool," I thought, but after a moment it dropped to 0 C. And then back to 125 C a little later. Well, I shut down quick and touched the CPU heatsink - almost dead cold, like it should be, as I had my CPU running at a fairly cool temperature. Possibly TOO cool, actually, given that I'd just been running something CPU-heavy for an hour. Started back up, messed with the temperature shutdown settings for a minute, rebooted. Now the system doesn't start up at all, no power light on the case (though the power LED sitting on the bottom of the motherboard comes on); keyboard flashes for a moment, but video is unresponsive, so I can't tell if it's getting to POST or not. No error beeps from the speaker. Most disturbingly, however, when I turn on power, I can hear a whine, almost like a tiny siren, starting at a low pitch and rising rapidly - even if the PC speaker is unplugged completely. This has nothing to with the main 'system power' switch, just the switch on the back of the power supply. It SOUNDS like it's coming from the back of the PC, but I can't localize it to the motherboard or PSU. I heard (I think from another TechSpot thread) that a whine like that indicates a leaking or faulty capacitor; can't see any that look damaged, though. Any advice? I'm not sure if the temperature sensor is on the CPU or the motherboard, so that's why I list the CPU, even though it seems to me as if the motherboard is more likely. I'm hoping we can figure out some way around replacing the motherboard, as that'd involve gutting my whole system given the age of the parts, and THAT'S an expense I don't need right after Christmas. Thanks in advance for the time to read all this, and for any advice you might have. It's appreciated!