Have you checked under the device manager in WinXP to make sure that all your peripherals are recognized? And like lingster mentioned, turn it on in the BIOS. It appears that there are a few people that have the same issues. The way I would proceed is to
A: Activate Touchscreen in Bios
B: Reinstall all drivers
C: ensure WinXP is recognizing the peripherals.
If this still wont work I consider to check on the hardware by disassembling it. Some very useful information right here. http://forum.notebookreview.com/panasonic/288352-cf-29-touchscreen-not-working.html
Good Luck