When i bought my computer the person said it had 512 ram but i dunno why but when i go to right click on my computer it sais i have 480 ram and also i cant figure out wether i have ddr or sd ram i tryed going to my run and typing "dxdiag" wich if u dont know gives u ur system specs for xp atleast and it still sais 480 ram and doesnt state wether i have ddr,sd,..... ram??? any help???