Try the following:
1) Locate the 'reset' button on the bottom of the mouse. (Tiny little black button on ours...)
2) Plug in the USB receiver. The blue LED button should light steadily.
3) Turn on the mouse. Hold it near the USB receiver.
4) Push the blue LED button on the receiver, and as it begins flashing slowly, push the reset button on the bottom of the mouse. This should synchronize the mouse and the USB receiver within moments.
5) If the blue LED button on the USB receiver begins flashing very rapidly, the mouse and the USB receiver are communicating, and the mouse should begin to work.
If it does not, the battery in the mouse may need to be removed and replaced, then the whole process started again...
If it works, you'll probably have to go into Mouse Properties in your Device Manager and adjust the response of the mouse, because the default settings are often positively crazy sensitive!
Hope this solves the problem. Cheers!