IS is a battery mouse? IF so, soundslike the battery is flat.
try these. Ad aware, spybot search and destroy, a squared.
These should sort it.
After you down load, remember to run the update option before you run the prog it'self
and don't forget crazy mouse, it can cause strange things
scroll down about one page, or search the site for 'crazy mouse' it makes the mouse pointer behave crazy (as you might expect).