If you're having trouble clicking the left or right mouse button and they seem to be 'sticking', it is likely that your mouse needs to be cleaned. If your mouse is old or if a sticky substance, such as juice or soda, has been spilt on the mouse, this may cause the button to stick when you click. This problem is frustrating, but fortunately it is relatively easy to fix with materials you may have around the house.
Unplug your mouse from your computer.
Use a screwdriver to remove the screw from the mouse. (There may be two screws.) Place the screws in a safe place so you do not lose them.
Open the inside of the mouse. Dampen a paper towel (it should not be dripping wet) and wipe the pads inside of the mouse.
Flip the mouse over and look inside the cracks where the buttons are. Use compressed air to spray inside the cracks at all angles.
Wet a cotton swab with rubbing alcohol. Run the swab through the cracks of the mouse buttons. Allow the mouse to dry completely.
Put the mouse back together with the screws. Plug it in and test your mouse.