The settings are not removed when the software is uninstalled. This makes it possible to uninstall and reinstall and still have all miners and configuration kept. It's important to never downgrade the version of Awesome Miner, as this can result in loss of configuration. Always reinstall the same version or later.
To reset all configuration, and start with no miners and all default settings, Awesome Miner must first be fully closed. Open the folder %appdata%\AwesomeMiner in the Windows File Explorer and remove all files where the name starts with "ConfigData". Next time Awesome Miner is started, it will be loaded with the default settings and no miners.