I have an old but nice Samsung X50 running MM which has a key between the touchpad buttons which disables the touchpad. Very nice, no-one like to brush against the touchpad while typing. It seems to be a hardware feature -- a BIOS style window appears at the top left of the screen when you press it saying "touchpad off"; and when you press it again it says "touchpad on", and so it is, but now the keyboard has no effect in X, I can type nothing except to meta-ctl F1 to the console. After a reboot the problem persists; and the only way I have found to fix it is to blow away .gconf are replace it with a copy I made in happier times.

Deleting/modifying .gconf/desktop/gnome/peripherals/touchpad/%gconf.xml does not fix the problem. There is no way to turn off the switch in BIOS without losing the touchpad. I would prise the thing out with a screwdriver if I could, but it's a work machine. This button is the bane of my life, hanging over me like a sword of Damocles.