ANT666_2

Hi I have 6gb of ram instaled and i am only able to use 2gb I have 2x amd optiron x64 6gb ram A 64x motherboard ... I cannot remember the chipset name All 6gb is recognised by bios but not windows I havent a clue what to do my mate says pae wont work as i have amd processors but i think different, there has to be a way i just cant find it. So any help will be appeciated Cheers Ant