Canon LBP7100Cn User Manual page 128

IMPORTANT
About [Cleanup]
Clicking [Cleanup] deletes all driver files and registry information displayed on the list, including the selected driver.
Normally, uninstall the printer driver using [Delete].
If this printer is not displayed
Click [Cleanup].
6
Click [Yes] to start the uninstallation.
Please wait a moment until the uninstallation is complete. (It may take a long time to uninstall the printer driver.)
When the following screen appears, click [Yes] or [Yes To All].
7
Click [Exit].