I think you may have this partially worked out. You should find the locations of the configuration folders in either the admin or all users area and delete or rename it again. If you have it in both you may want to do this in both of them.
Once you have done that you will need to open the AEM and delete the extensions that you see listed here. This should give you a clean config to start the installation from. Let us know if you have any problems after trying it this way.