I had trouble getting my Dell XPS M1530 track pad/touch pad to work when I updated the BIOS from A07 to A09. However, it is fairly an easy fix.

Edit your ‘/boot/grub/menu.lst’ file with:
sudo gedit /boot/grub/menu.lst

Then add:
i8042.nomux=1

at the end of the ‘kernel’ line. It may look like below:

title		Ubuntu 8.04, kernel 2.6.22-14-generic
root		(hd0,0)
kernel		/boot/vmlinuz-2.6.22-14-generic root=UUID=446ea0c-57b1-4112-939c-
3f1d74be9f5f ro quiet splash i8042.nomux=1
initrd		/boot/initrd.img-2.6.22-14-generic quiet

Save the menu.lst file and reboot. This should get your track pad/touch pad working.
Reference from Ubuntu Forums.