I have suddenly lost the TouchPad / TrackPad functions on my Windows XP 3 Laptop, which is an Acer Aspire 5001 WLMI.
The Mouse works OK, but the TouchPad does not move the cursor or produce a click. I have tried the TroubleShooter, which while it identifies the Pad --- Synaptics PS/2 Port --- treats it as another Mouse. In fact unlike the Mouse there is little relating to the Pad, no editing of settings, etc. despite it being an integral part of the PC (which the Mouse is not). I have looked at updating the Driver but Windows reports there is no later / better Driver available.
Would you have installed any software just before this occurred? I recently installed some bad software that also caused my touchpad to fail (intermittently). I also tried to download (was nothing available) and tried to use a backup of my touchpad driver, but XP couldn't "find" anything adequate to reinstall either. It recognized my touchpad in the same minimal manner.
I (manually) uninstalled the bad program and used Last Known Good Config from the Win Advanced Startup menu, which fixed my touchpad problem.
The XP is still without use of the Pad. Devices (if I remember correctly) lists the Touchpad but reports that it is working correctly, though in fact it is not working at all!
That is typical, anything that is malfunctioning I have only seen it continue to report that the device is working correctly. So much for XP auto assessment.
As for if you really do have to reinstall the touchpad driver, that seemed it was going to be a very difficult process and I can't help you there.
I wonder if you could have had a hardware failure in the touchpad. Try searching for any kind of testing or diagnostic tools, if they exist.