There are many reasons behind nonfunctional wireless mouse.
Some are discussed here: Bad USB Port Sometimes the connection between the receiver and the defective USB port in the computer can be the cause of nonfunctioning of wireless mouse.
In this case, the connection is cancelled and reconnection should be attempted through another USB port in the computer.
For a desktop computer, the USB ports in the back are recommended.
Device Interference Wireless signals of the mouse can be hampered by the presence of other similar gadgets in its vicinity.
This causes interference of signals between the two.
So, it is wise to remove other wireless devices like cell phones, cordless phones.
Even metal objects can create similar obstacle, they need to be removed as well to obtain maximum functionality of the mouse.
Software and Firmware Issues Most of the USB gadgets can function instantly when plugged in.
But in case of some mice there are new software provided by the manufacture which needs to be installed.
This device driver software can be installed by visiting the manufacturer's website.
After updating the software you will have to follow the reconnection and resynchronization steps another time.
Warning If the problem prevails even then, check the mouse.
If there is crack or if it shows any other sign of physical damage, stop using it.
Using it can be dangerous.
If the product is within its warranty period return it and get a new one.
Now that you are done with the knowhow of the problems enjoy using wireless mouse.