Hi,
On the bottom of the mouse is a small button that has to be pressed with the end of a toothpick or
a paperclip.
If nothing works check with the Seller or Microsoft Support.
Wireless 3000 has a 3 year warranty
Warranty
http://www.microsoft.com/hardware/Warranties.mspx
Microsoft Hardware Claims
MS Hardware Support and Warranty Claims & Tech Support 1-800-936-5700 for MS Hardware.
They will replace the mouse if it can't be made to work properly if it is still under warranty.
Mouse has 90 day tech support from date of 1st incident which should mean this will not cost
you anything (unless you have called about the mouse in the past).
Hope this helps.
Rob Brown - MS MVP - Windows Desktop Experience : Bicycle - Mark Twain said it right.