Right click on My Computer icon
In the drop down menu choose Properties.
When new window opens click on Hardware.
Click on the Device manager Button
When that window opens and brings up a list...double click on Mice and other pointing devices.
Your mouse should show up under that after you double click.
Right click on the one listed under there.
In the drop down menu click Uninstall.
Now hit the Windows Key on your keyboard (two keys over on either side of your space bar).
When that comes up, use your up and down keys to turn off computer.
When that choice comes up use your up/down keys or tab button to pick the restart computer option.
Restart your computer.
When the computer restarts it should reinstall the mouse.
Hope that helps.