My Music Thumbnails

When I play an album from the 'My Music' folder, the
thumbnail can sometimes change to a picture of another
album. Also the folder type often changes, ie. the folder
type will change from a music folder to a pictures
folder. And the problem is that when I right click in the
folder to arrange the WMA's into their track number, I
only get the options 'picture taken on' and not the
option to 'arrange icons by track number'! My solution to
this was to add a dash onto the end of the album name...
johnnycash- which is usually just a temporary fix. Any
help for this very annoying bug?