Spontaneous reboot I'm at wit's end; my system is rebooting on its own. When I got this system, it didn't happen, but lately it's happening more and more, and it's happening sooner after powerup. An odd sound accompanies this, from the motherboard somewhere near the memory slots, reminiscent of the sound a steamkettle makes before it whistles. I was concerned it was a problem with my CPU overheating, so I purchased a better heatsink/fan and replaced it, I've added fans to the case, removed two HDs for concern they were heating up the ambient in the case, etc. Then I thought it was the video card overheating, pulled it and ran off the motherboard's video... same thing. Runs for a while... BADOOP, reboot. Current thought it that the northbridge or southbridge is overheating, but I don't get why it would be doing that now. I did remove the heatsink from the northbridge, and take a look... reapplied new paste and reattatched. Currently I'm running with the side off the case, with a fan blowing into the side, but even that doesn't always work... and it sure is loud.