I got 2 GB of ram (two cards) and inserted them in the two available slots, next to the two 256MB cards. Computer made three long beeps when I turned it on. Then got a message that says: "The firmware has detected that a CMOS Checksum error has occurred." Turned it off. Took 1GB of RAM out. Turned it on. Computer made the long beeps. Then got a different message: "The firmware has detected that the memory has decreased." And my monitor wouldn't work. Turned the computer and monitor off. Took the other 1GB out. Seems to be working fine now. But I'd really like to add some RAM to this computer. Thought I had exactly the right kind, but maybe not. I could buy RAM from the computer mfr, but it costs about $40 more, and would have to wait for it, and it still also might not work (even if it comes from the mfr), and would have to ship it back and pay for shipping. Any advice?