Here's a couple more ideas that may work:

- on our HP laptop, the touchpad has a small indent in its top left corner. If you double tap that with your finger, it disables (temporarily) so you can (say) type without affecting the touchpad (double tapping again turns it back on)

- on our netbook, there's a Fn + F9 that similarly turns the touchpad on and off

Good luck!
LLOYD