When iTunes imports media files it reads data from any internal tag which it uses to provide the details such as song name, album, artist, track number, etc. Normally when those details are completely missing iTunes will use the filename without extension as the song name, set the artist to Unknown Artist, the album to Unknown Album, and all other details will be blank except those such as duration that are calculated from the audio data. I have a script called TagFromFilename that can read details present in the filepath if the tracks are in a standard ..\<Artist>\<Album>\## <Name>.<Ext> layout, and apply that information to the tracks. For it to work you have to turn off the Keep... & Copy... options under Edit > Preferences > Advanced before adding tracks to iTunes so that it won't copy or rename the files during import. Once the metadata has been updated you can turn those features back on and/or consolidate the tracks into the media folder.
At the time of posting my webhost appears to be down and I'm getting a 503 Service Unavailable alert when I use the link. I don't know how long it will take for the site to come back up but they are supposedly working on it.
tt2