Welcome to the forum, NorahM
You must have played around with MB's File Organizer
But if that's the case, then the situation is still reversible...to some extent though 'cause this works flawlessly when all your files are properly tagged.
So using the same File Organizer, you can tell MB to organize your files in C:\Music using the following structure: <Artist>\<Title>.
But before that...
Personally, I would create a virtual tag that sets the artist name to 'Unknown Artist' for all songs without artists.
This is so that, when MB does the re-organizing, the songs without artists would be placed under the Unknown Artist folder.
So steps to take:
1. In MB, go to preferences -> Tags(1) -> under custom tags...define new tags
2. Pick a virtual tag slot and use the following formula to weed out songs without artists....$If(<Artist>="",Unknown Artist,<Artist>)
3. Go to your main library tab and select all the files.
4. Right-click -> Edit
5. In the tag editor, select 'Rename'.
6. The File Organizer will open up and inside it...under the "to folder"...type C:\Music
7. In the naming template....type \<Virtual1>\<Title>
(in place of virtual1, use the virtual tag that you picked in step 2)
8. Finally... hit 'reorganize'
After all that, I believe your files should be organized the way you first had them.
Concerning the 50 songs that will be missing title names, we can discuss that later on once you get the reorganizing done.
As a precaution, please attempt this later on (maybe some 5hrs later) when no other forum member has suggested something different and better to what I have.