[Bloody Sam Roberts]

I have had 3 computers and several mice.

And it continues to happen? On 3 computers?

Clean off the sand and gravel from your desktop or mousepad.

Seriously though, open up the bottom of your mouse and look at the wheels that are moved by the ball...if you don't have an optical mouse with the LED on the bottom.
You may find a lot of lint and crap wound around the wheels. Cleaning this off will help a lot. It has for me in the past...until I said "Screw it" and went optical.

[since1868]

I do use a opitical mouse.