I have an older 15" G4 Powerbook (before the recalled Powerbooks with the RAM slot failures) that has recently been experiencing some speed issues. To my dismay, when I checked my 'About This Mac...' I no longer had 1GB of RAM, only a lowly 512 MB. Tonight I sat down and started swapping and removing my two sticks of RAM and as it turns out, something is up. With a 512 stick in the lower slot, System Profiler tells me I have 512 MB of RAM and that the upper slot is empty. When I put the other stick in the upper slot (leaving the lower one in), System Profiler now says I have 512 MB of RAM and that the lower slot is empty. Does this look to be a (out of warranty) logic board failure? Is there anything else I can try to do? On a related note, when removing the screws from the RAM panel on the bottom of my PB, one screw fell into my Powerbook, never to be seen again. Is this going to cause any problems down the line?