Patriot 2431 Ram - to access the ram you need to remove the keyboard. There are two covers underneath the keyboard - the one near the centre with two screws holding it in place is the location for the ram. Removing the keyboard is slightly fiddly, but not impossible. An extra pair of hands might be useful. There are three lightly spring-loaded release catches at the front of the board, one towards each corner and one just to the right of the touch pad. Suggest you investigate with a good light or torch and a watch-maker's screwdriver. The three clips spring backward to release the keyboard - my son and I managed to get it out OK (and put it back). We started with one corner first (left when facing screen), then released the middle clip and finally the other corner - the board then just slides forwards and out.
The ram appears to be 2.5volts, 200 pin SoDIMM and we think pc2100 (but not quite sure - can anybody advise/confirm?). There is a vacant slot for a second SoDIMM, in addition to the original.
Thinking of upgrading but haven't purchased new ram yet. Have otherwise been well-satisfied with the notebook for the price paid a year ago.
Mike