Why did you rename the .itl file? iTunes expects to open the last library it was connected to when it is launched. If you rename the file iTunes may complain the file is missing, or if the file was on the default path of C:\Users\<User>\Music\iTunes\iTunes Library.itl it will create a new empty library as if it had just been installed. iTunes doesn't scan the designated media folder for new content. That can be added manually with File > Add to Library, but these will be new imports, added today, and any ratings, playlists, play counts, etc. that were in the old library database and not the file tags will be lost. If you have any .wav files in your media folder adding them to a new library may lose data that is currently represented by the file path. If that is the case please, at the very least, turn off Keep Media folder organized before moving forward. It may still be better to try to revert to your old library.
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