The USB Mobile Monitor allows you to connect your Android mobile phone
or tablet to your PC with a simple USB Cable. All that is required is
the download of the USB Mobile Monitor App on your device and the
installation of the USB Mobile Monitor software on your PC.
The USB Mobile Monitor allows you to replace the keyboard, mouse and
computer screen of your PC with a single device.
This is a kind of built-in system shipped with your device I guess. So,I think you need to install the APK version to get this works. It can be found here. Then follow the usage on this page.
After that, try enabling USB Debugging again.
For the rooting part, follow this guide on XDA Developers.