I have a HP Compaq dc7800 SFF KMAT with 2GB of memory that I am tring to increase by adding 2 more sticks or purchasing 4 new ones. The sticks say they are Ramaxel, 1GB 2RX8 PC2-5300U-555 LF. I have searched the various memory vendors including the non-existent Ramaxel??? and found nothing that comes close to the 5300U-555 spec. Does anyone have a clue for this? Thanks in advance.