Help with trackpad stupid mistake in a MBP 5,1

[GeneralSunTzu]

I have a very jumpy cursor on my MBP 5,1.
Followed what's in the wiki, installed pommed, etc., all to no avail.
In one of the latest attempts I unchecked by mistake the box, in "trackpad", which says "use trackpad", and of course I now have a frozen cursor, without any idea on how to defrost it...
I have no external mouse at home.
Can I do anything different from re-installing JJ again?
Thank you.

[GeneralSunTzu]

Bump...

[alexmurray]

Hit Alt-F2 then type gnome-terminal and type in the following:

gconftool-2 --toggle /desktop/gnome/peripherals/mouse/touchpad_enabled

this should reenable your trackpad.

[GeneralSunTzu]

Thank you, I tried, but the cursor stay frozen.
Now, I had previously amended a file named …policy.inf I think, but I cannot remember the complete path name.
Using your trick I can gedit it and maybe stop this disaster.
Alternatively, a pal is bringing me tomorrow a USB mouse, which should work (I cross my fingers...).
Thanks for the head-up. Won't forget it.