@DjVentsy > What exactly "isn't working"? Rekordbox isn't opening? You can't add files?
If your username in Windows is "Ventsy" then you would be looking for:
C:\Users\Ventsy\AppData\Roaming\Pioneer\rekordbox\datafile.edb
If you have hidden files enabled, then you won't see it - you need to go to Tools > Folder Options > View > Show hidden files, folders, and drives.