My mouse experiences uncontrollable movement from time to time,
seemingly more when I am connected to the internet, although that may just be
coincidence because I usually am.  The mouse is just a touchpad one on a
laptop.  It repeatedly opens up my start menu and either moves around icons
on there, or opens programs.  
    It also sometimes closes whatever windows I have open.  I have done
multiple virus scans and spyware scans with different products, and nothing
has turned up.  It has happened regardless of what wireless or cable
connection I am using.  Sometimes I can stop this happening by holding the
right click button for several seconds.  
    After this happening four to six times over the course of the time I'm
on my computer, the mouse will freeze, either at the bottom left corner of
the screen on the Start menu, or in the very middle.  On some of these
occasions, my computer makes a loud beeping noise if I try to move the mouse.
It sometimes takes as many as 5 restarts for it to unfreeze, though usually
shutting it down and waiting several minutes before turning it on again will
work.

Hope I gave enough info ;)

-K