ok first off this morning my computer was COMPLETELY fine like everything was running the way it was supposed to run.. then after i got home from school i turned it on.. then it said "CPU failed due to system overclocking" or something like that i forgot but yeah, i have no idea what happenned! then when i it said reset my CMOS or something? but i didnt know what to do so i just clicked F1 to continue.. but when i started up i noticed some lag in my games.. then i checked on CPUZ my CPu speed was at 1000 Mhz!! and my multiplier was at 10.5! so then i restarted and went to the BIOS and it was still at 166 Mhz, and the multiplier was still at 11x, so i saved n exited.. then when i started my CPU speed started going up to 47C idle! and wtf.. thats REALLY unusual.. please help! i dont know whats wrong.. now my speed is back up to 1.8ghz but my CPU has been heating up more than usual.. whats wrong with it! >.<

It's difficult to say what your problem is, but I do question what you wrote. Unless you have an old 2500+, the multiplier is locked at 11x & cannot be changed. Even if it did drop off to 10.5x & the FSB to 100mhz, your speed would have been 1050mhz, not 1000mhz. Maybe your motherboard battery is getting weak. Did you check your other BIOS settings to see if anything else changed? Is 47C at idle high for your CPU? What temp does it normally idle at? Asus A7N8X-X 2500+ Sempron @ 2100mhz 10.5 x 200mhz @ 1.80v 512mb PC3200 Ti4200/8X 128mb WDC 60GB

and yes your right im sorry the speed WAS at 1050 Mhz but i didnt think the 50 mattered but i guess it does so yeah.. it WAS 1050 Mhz.. and i have no idea if it was because it was winter or not but usually it would idle at about 40C or something.. but maybe i havent been checking it right and no i dont think any other settings changed.. none of them changed at all because right when i went into the BIOS the settings were the way they were supposed to be, but for some reason when i turned it on when i got home it went down.. but i dunno is that normal? am i supposed to change the battery?

btw jam what does your CPU usually stay at? just so i can compare and see if mines are high.. well right now its idle at about 45C.. but when i play counter strike it goes up to about 47C.. and when i play WoW it goes up to 49C..

I still question the 10.5x multiplier setting. Your CPU would have to be well over a year old for it to have an unlocked multiplier. All Bartons produced after late Oct 2003 are "super locked". Right now, my mildly overclocked 1800+ Tbred (8.5 x 200mhz) is running at 31C. That reading is from Asus Probe.

ahh.. well it seems my computer is running like it usually would.. not any lag or anything.. openned it up and nothing was burned or anything.. is 45C an ok idle temp? or is it too high?

Going back to your original problem...do you normally shutdown your PC every day or is it usually left on? Did the main power get disconnected from the tower (cord unplugged or surge protector turned off)? I ask this because if the motherboard battery is bad & you're not in the habit of regularly shutting down your PC, you wouldn't realize it was bad until you did. Even so, if the power isn't totally cut to the tower, the PSU keeps the board charged via the +5vSB (standby) rail, so it's possible the BIOS wouldn't reset even if the battery is weak...but if the plug is pulled, it would. 45C is acceptable, but lower would be better. What is your average room temp & system temp? Your system temp should be within a few degrees C of room temp...if there's a large difference between the two, your case cooling may be inadequate or poorly setup. Then again, temp readings are sometimes inaccurate.