I have several albums and files named incorrectly like "Track01.mp3" that don't have any ID3 any tags either. Tagging software like Tag&Rename can find ID3 tags for full albums only.

Is there any way to tag single files? Yes, you can correct missing tags with freeware Picard Tagger and shareware Magic MP3 tagger. Both use Musicbrainz database and both were not very good in my tests. Not only I couldn't tag some of my files with the above mentioned programs, I didn't really like the interface of Picard Tagger and Magic MP3 tagger.

As for Replay Media Catcher, it can tag MP3 files while recording streaming media, it doesn't work with local files.

The only solution I have now is to tag such files with Replay Music. Oops! You can say that Replay Music re-records the song, so besides wasting your time, you lose quality with it. Although I can't do anything with the time factor, you can import ID3 tags from the newly recorded files (for example Tag&Rename can import ID3 tags). Voila!