Ram doesnt read up correctly

[mysticjon]

i just bought some kingston 2gb dual channel ddr2 pc2-5300 ram. the problem is that my computer only reads up 1790mb of physical ram and in the bios it reads up as 1.8gb. i updated my bios and too see if it was just an minor flaw. It used to read up as 1919mb before i changed my product key...is it possible that since the product key i used read up my old ram settings which was 1790mb, my old computer had a sempron and used ddr ram and the old product key, but i changed the product key on my new computer to the one my old computer used. does anybody know how to resolve this? i heard that some kingston ram sticks were faulty..