You do not delete or move the folder that has all your music files. iTunes is a media player that plays music files that are on your computer. The music you have in iTunes library refers to the location where the file is. Once the file is moved or deleted, it won't play anymore and there will be an exclamation symbol before the music indicating iTunes could not locate the file to play.
I understand that but the same songs are in the iTunes music folder within iTunes. So, the songs are on my computer twice and I would like to get rid of the old Sansa folder. When I do a get info on one of these songs it says the location of the song is the Sansa folder. How can this be changed so that iTunes does not look for the song there?
If the same music file appears in iTunes media folder, then there should be a duplicate in your iTunes library. Can you confirm that?
If so, we can deal with finding n deleting duplicates.
How to find and remove duplicate items in your iTunes library