Having Artist, Album and other information is handy on iPOD, iPhone etc. If you don't have this information you can add/edit this
Navigate to the folder where the songs are stored.
Click on the song you want to edit to highlight it. RIGHT click the properties.
The properties box will open. Summary tab, Advanced.
Make your changes. Pick the field you wish to change. It should be highlighted in blue. Simply start typing what you want to put in the field. If there is anything already listed you don't want, delete it.
Click apply to save the changes.