Please check the following points.
* Before you check, please make sure the computer's operating system can be worked with the mouse.*
(1) Check the battery: battery's power is enough to work,charge a new battery.
(2) Check the connection: the receiver should connect with the PC(notebook) directly, 
please do not connect with any extension cord. (such as: USB extension cord, plug adapter, usb adapter cable….)
(3) change another USB port and try it again.

If the test results for your mouse are:
(1) The battery has been replaced with a new one.
(2) It is directly connected to the computer's USB port.
(3) It has been plugged into other USB ports but still does not work.
Please refer to this manual pairing process in the DOWNLOAD page.