I've lurked on Tom's for a long while, but never posted till now. You all seem like a pretty smart bunch, so I thought I'd ask for some help.
A couple months ago, I overclocked my Dual Core E2200 from the stock (a pathetic 1.8 GHz, as the FSB was set to nine out of the factory). I Brought it up to a nice, round 3.0. The processor is generally expected to go up to 3.1 - 3.3 without much trouble, and it worked for some months.
Yesterday, however, I woke up to find out my computer was already on. I gamed a bit on it, but I noticed my framerates were down by a fairly wide margin. Apparently one of my family members had turned it on in the morning, and it booted up and (I assume) the dual boot kicked in and undid the overclock. This is strange because the overclock up to 3.0 was not only very stable, but never had heat issues. I didn't think much of it at first, and went ahead and overclocked it again from scratch. But now it won't even pass 2.57 GHz! Any more than that, and the computer kicks into dual boot, resetting the clock speeds to factory defaults. It doesn't even POST.
I'm somewhat baffled by this, as it was so easy to clock up, and would only ever have a dump maybe once every 3 weeks if it was seeing usage practically nonstop. Resetting the CMOS does not help, nor does flashing the BIOS.
My specs are:
Intel Dual Core E2200 CPU
2 2 gig sticks of Corsair RAM
gigabyte G31M-ES2L motherboard on Award Modular BIOS v6.00PG
Nvidia GeForce GTS 250
575 Watt PSU
Cooler Master thermal paste
Edit: The heatsink is a 12V masscool, and there are a lot of fans in my machine. The temps have always been stable, so I doubt this is the problem.
A friend of mine has the exact same problem--but it's probably you so that's not very helpful.
My best guess is that you look into that dual bios. Can you choose which bios to flash and flash the second bios? Or can you choose which bios to use since it's probably the old one giving you trouble? Make sure to backup your original bios, just as a precaution.
Likely your dimm ratio has lost it's setting and when your overclocking it's setting your memory speed faster than it can handle causing boot failure.
Change the fsb/dimm ratio back to where the ram runs at or under 800mhz (or whatever speed your ram is).
Wow, I feel like a regular idiot now. Sure enough, bumping the CPU past 2.58 brought the dimm ratio (which had defaulted back to automatic) over 800mhz, which the sticks simply could not handle. Thanks a bunch everyone!