There's a freeware named MP3 Tag editor but I can't find the page to download it.
However most of the mp3 tag editors will recreate the name of the file from the information stored in the tag.
An example is this shareware.
http://www.1st-mp3-tag-editor.com/index.htmYou load the software, select the folder with the music, select the songs nad select rename file from tag.
How long it will take you will depend on how many songs/folders you need to rename.
Also if you install ITunes, it will read the tags not the names of the file so you can choose the song, how ever the file names will still be strange.