WordPress site referencing two different install folders

I’ve taken over a site that has an installation of WordPress in the root folder, and then another installation in a different folder with the exact same files. I have no idea why the previous admin did this, but now I have to deal with it. I want to consolidate the project to a single folder, but different portions of the site reference different folders. Both folders have the exact same files (or very close). For example, the home page references the template file “home” located in the root directory, but the rest of the site references the “about” template file located in the other folder. I want them to reference the “about” template file located in the root directory. Anyone know why it is doing this and how to change it? I tried just deleting the files, to see if it would look for them in the root directory, but it just returns an error that the file is missing.