Erratic pointer on a Mac Book Pro

Erratic pointer behaviour.

I have a Macbook Pro, 2.4Ghz, Intel Core, Duo with 4 Gb 667 Mhz SDRAM and Leopard installed.

Every so often and at random times, the pointer starts to behave erratically. It darts around the screen, opening contextual menus, creating new folders , pulling down system menus.

I take my hand off the mouse and it carries on. I have disconnected the mouse, disconnected all peripherals, including hard drives, tablet, printers etc. I have repaired disc permissions, trashed preference panes, and even re-installed the Leopard system software. The problem still persists. Any thoughts?

email: [email protected]

Check if you have the latest firmware update from Apple's site.
Also, even if you are on 10.5.8 try installing THIS
The combo updates are often magic pills for a lot of issues in OS X

If u want to keep down your spam quota then good plan to remove your email address. If problem persists then in interests of troubleshooting try plugging in an ext mouse to see if that acts the same way.

Have just been talking to a MBP owner in the USA who had similar issue, and his has just gone it for a new Logic board.
Looking at your specs you must be close to 3 years;
check this out;
Apple Extends MacBook Pro NVIDIA GeForce Service Policy to Three Years