remote not communicating to computer

The remote works, in that it can power the projector on and off, but the page up/down buttons do not work in PowerPoint. I've checked the cable connecting the projector to the computer and it seems fine. Had the same problem on two different computers, both notebooks with built-in mouse pads. Could there be a conflict between the keyboard/mouse drivers in the notebooks and the remote simulated keystrokes? Or could those two particular buttons on the remote have just stopped working? Haven't used the projector in months, but it has been stored at room temperature in a humidity controlled environment.