I have just purchased an emachines E4506 it has a pentium 4 3.06 Ghz processor an 80gb hard drive dvd/cd rw 512mb ram. I had a previous discussion regarding the 512mb ram been only 368, but i found out that the graphics take some of this. I want to add some more memory but i look on ebay and theres so many different types of ddr. Such as PC2100, PC2700, CL3 non-ECC, 184 pin. Can anyone help me track down the exact memory i need to buy please.