Cpu running at half clock rate

i've had my amd processor for a little over three years now. it has always run at about 2.1 Ghz. a couple days ago i reset my bios to its default settings. yesterday i went to my windows->control panel->system and it says that my processor is only running at 1.24 Ghz. this probably has something to do with me resetting the bios right? how do i change it back to 2.1 Ghz?

the normal rate for the cpu is 2.1, i wasn't over clocking or anything.

What is the model of your processor?
It is possible that in resetting your bios, it decreased the front side bus and / or the multiplier. Find out the model of your processor and use google to look up the correct front side bus (fsb) and multiplier. Then check that against the bios settings, changing if needed.
Note that if you set your fsb too high for the computer, it will not boot and you'll need to clear your cmos.

Cheers