problems with my home built computer

[killzone2k3]

i just built a ew computer. here are the specs. chaintech ct-7njl6 mobo amd sempron 2800+ processor maxtor 60gb 7200 rpm hd 2 ultra 128mb memory sticks.(i have them dual channeled) radeon 9550 128mb graphics card ultra 400 watt power supply i havent installed an OS yet. My problem is that when i first boot up my comp it tells me that i have only a 1.2ghz processor instead of a 2.8ghz. it also says that the processor has been changed and i should reset the cpu information in CMOS setup. The problem is i cant find out how to reset my information in CMOS setup. Please help.

[habbojane]

your sempron doesnt run at 2.8 its 2800+(your actual clock speed is 2.0)I it think your gonna have to go to your bios and manually change the bus speed to 333mhz. 1.2 on that sempron means its at defualt 133mhz