Hi, well it all started with an AMD Athlon XP "Barton" 3000+ which I had a problem with as described here.

So I returned that, and got this. Same FSB as current 2100+ so it should be all good. I put it in, and the computer spits out beeps...high pitched beep...then a low pitched beep...over and over and over again before I have to turn the computer off. The CPU fan and the system fan all stop working too...the only thing receiving power was the speaker from what it sounded like.

I return that CPU assuming it was the CPU and ordered another from zipzoomfly.com. A 2400+ Athlon XP clocking at about 2 ghz which can be seen here .

So I get this CPU and put it in, and same exact problem occurs so I go through clearing the CMOS, taking sticks of RAM out, etc and nothing works. So I take it out, and put my 2100+ back in and then I go to the BIOS, change the FSB settig to what it was, 166mhz, and then save and restart. Windows begins to load and at the Windows2k startup screen with the blue bar at the bottom loading...the computer shuts itself off, well the fans and HDs as far as I can hear, and the speaker begins its beeping again until I turn it off. I restart the computer, and it loads everthing again but same thing happens at the Windows screen. I go back into the BIOS, cahnge the FSB to 100 and now it seems to be working just fine, only at a lesser speed. It is clocked at 1.3ghz when it should be around 1.7-1.8ghz.

I know this has to do with the FSB but why does it not allow 166mhz anymore? Did I fry something on my mobo?

There are also no jumpers to be changed as I've been through my manual almost 40 times already.