G’day folks. This guide and the following comments helped me to get the old swollen battery out. I used a pair of pliers to loosen the screws, as the flat blade screwdriver I had was not enough. The track pad now works again. I did not replace the battery, and the machine seems to be working as normal while running just on mains power, despite warnings on other forums that it would loose performance without the battery. Thanks a lot to all contributors.