Wich RAM card should I get?

How the... I believe that DDR2 and DDR are not physically the same size, so how did you get it into the slot?

Well anyways, sounds like you got the socket 939 Athlon 64, it uses DDR RAM. You have to get DDR RAM, preferably DDR 400 with good timings.

they are different, you cant use a DDR on DDR2 slot, or a DDR2 on DDR slot.

How many beeps ur motherboard do?when its beep, most of the case are, or theres no memory ram, or no graphic card.