Factory reset is resetting all the settings to defalut and deleteing all the channels, and can only be done by going to the menu>instalation etc. like you pointed out.
Factory file is used to overwrite the current file you have installed, but it will not reset any of the settings.
You can try loading the factory file, to see it you can get in the menu and then do a factory reset. Just write down all your antenna settings, because you'll have to rescan all your birds.
