Does anyone know if the sound files that are downloaded or automatically added when talking to friends on your contact list, are located on your computer somewhere or do they play from the database its self??  If there on your computer, where do u find them and if u were to delete them will they still work in messenger plus?

All sounds that are played are downloaded and saved on your hard disk and added to your database.

On XP this is in the following folder: C:\Documents and Settings\All Users\Application Data\Messenger Plus!\Custom Sounds

If you delete the actual sound file messenger plus! will download it from the database.