You can customize how your touchpad buttons function using the Logitech SetPoint mouse and keyboard software.
NOTE: If you don't already have SetPoint installed, you can download it. See answer 360023356413 for instructions.
To change the task a touchpad button performs:
Launch the Logitech SetPoint mouse and keyboard software.
Start > Programs > Logitech > Mouse and Keyboard > Mouse and Keyboard Settings
Click the My Mouse tab at the top of the SetPoint Settings window.
Select your touchpad from the product drop-down menu at the top left.
Choose the touchpad button you want to customize in the Select Button field.
Choose the task you want to assign in the Select Task field.
NOTE: You can click the "?" icon for descriptions of the tasks.
Click Apply to save your settings and then OK to exit SetPoint.