I found the following at click here (last post).
After much trial and error and searching for non-existent service manuals I have managed to work this out. The 2nd RAM slot is under the keyboard. To get to it - open the laptop and push the screen back as far as it will go, so that the laptop is opened flat on the worksurface. See the photo here click here Gently prise off the plastic strip above the top of the keyboard (1). This is the one that contains the power and launch manager buttons and lights. Remove the two screws holding the keyboard in place (2). Lift the keyboard and tilt it forwards (3). This saves having to disconnect the ribbon cable at the front of the keyboard. Replace the RAM module in (4). Put it all back together! Good luck.