For new installations
To activate using key file, Close your internet connection...setup the program, and select trial license.
It will have an activation error message "server name cannot be resolved", click ok and you should reach a page with "browse" button, select that and search your key file and click next to activate.
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For changing keys when keys are blacklisted
To change keys, close your internet connection, then click at "License" found at bottom of the window when you open Kaspersky. You see a red color "X" sign.
Click at that sign to delete the key, and then select activate new license. It will have an activation error message "server name cannot be resolved", click ok and you should reach a page with "browse" button, select that, search your key file and click next to activate.