change or modify or overclocking or down clocking your bios setup can damage your motherboard and hardware.
press repeatably the deleted key weh you turn on your pc. it will bring you to the bios setup.
go to AI overclock Tweaker tab
Ai Overclock tuner = manual
cpu ratio = got to be setup in accordance to the spec
fsb frequency =got to be setup in accordance to the spec for the cpu
fsb strap to northbridge= got to be setup in accordance to the spec you want to run your pc at
dram frequency = by playing with the fsb,cpu ratio, to get it to what you want
dram timing control = very important to get it right
then once back to os run cpuz
and head over to memory to check the dram frequency
dram frequency 400 = 800 mhs 533 = 1066
you must set the clock and voltage the correct setting to make this work
all of the settings in the bios are a risky business to play with if you do not know what you are doing. if you do not know what you are doing you might need to flip your battery on the motherboard to reset the bios. improper setting can or will cause permanent damage to anything it is connect to. mother cpu ram hard drive video card lan audio pcie might be burn... adjust at you own risk or go see professional help.
best thing to do is to get the store to do the installation.
and the motherboard can be picky on which ram it will accepted.
ie my board is a p5q-em not friendly to mushkin. so I install a twin dominator corsair 4 gig kit 2 x 4 for a total of 8gigs
dram voltage ad nb voltage also had to be played with to get this ram properly set.
the motherboard by default settings view it only at 800 mhs and not 1066 ddr2.
anyways my advice is to get professional help. playing around with the bios is like playing an experiment on pc. you never know what can happen. ie I went threw 3 power supply. from 550 watts to 1250watts. before I found a stable power supply for my overclock pc.