new peoblem

ive got a asus p4b-266-c. bios version 1006. i just got done switching vid cards and ram. now when i go into the bios i cant change the cpu fsb or anything. it doesnt let me. it worked after i switched everything . then i rebooted and now i cant change it. its a p4 2.4 , 512 megs ram. any help and info would be appreciated

ok, i posted this in the wrong spot, sorry. i cant delete it sooo. sorry bout that.