I once disabled my touchpad because I would rub against it while typing and it would move my mouse elsewhere. I have since re-enabled it from the same place (system -> preferences -> pointing device) but it remains disabled at next boot up.
I know it's a per-user setting, because when I logon as another user to the same laptop, touchpad remains enabled..
Not having a mouse around and a touchpad that is disabled is most distressing, as I get stuck! Anyone know how to renable the mouse for a user, or just to reset the settings of the touchpad..