The standard RAM in this machine is 256mb. I am trying to upgrade by
adding a 512mb card (specs say it's upgradable to 1GB). I am using an
ULTRA DDR Memory (PC2700, 333mHz) which is compatible with PC2100
266mHz). When adding this card to the 2nd slot, the system is not
recognizing it. I took out the original RAM and added only the 512mb
to the 1st slot and the computer would not turn on at all. Finally I
put the original 256mb card in the second slot and the 512mb card in
the 1st slot. The machine now runs, but it still only sees 256mb.
What else can I do/check?

Thanks.

Joe