Unfortunately, the user guide that you can find, if you go to Start > All Programs > Lenovo > Lenovo Quick Start > Lenovo Quick Start Installer > Help doesn't provide any instructions that can help you to change the program you open with this tool. It shows only how to set the program after you install Lenovo Quick Start. My recommendation is to uninstall Lenovo Quick Start from your PC (Control Panel > Uninstall a program) and then download and install its latest version form the official web page. In this way you will be able to reconfigure the software.
