I'm sorry about the issue. Do you have windows xp, vista, or 7, or 8, or mac computer?
Can you open the Logitech SetPoint program on your computer and adjust the mouse buttons' setting there? Full instructions:
If needed, click on Start -> Control Panel -> (Hardware and Sound if available) -> Mouse, then adjust the mouse buttons' setting there.
If needed, you can download / install the Logitech SetPoint program at the Logitech website below:
, then open the Logitech SetPoint program, then adjust the mouse buttons' setting there.
Please reply at the box below to continue troubleshooting. Thank you,