Step 1 : Make sure that the dongle is taken out of the mouse and batteries are inserted.
Step 2 : Donot insert the dongle in the CPU/Laptop before the pairing is complete.
Step 3 : Press and hold the following keys on keyboard and mouse together at the same time for a span of 3 to 4 seconds:
(ESC + K) in keyboard
(Left button + Scroll button + Right button) in mouse.
Step 4 : Insert the dongle on the CPU / Laptop.
Step 5 : Kindly repeat the procedure if required.