I am encountering the same problem. I had problems with windows media and so removed all traces on my pc of the songs on my clip by using Windows Media player (and renaming all folders on my pc that ties it in with the player.
When I reopen windows media player it can’t find any music on my clip but when I turn on the clip it shows up when I “play all”. Same thing when I open Windows Explorer, it can’t seem to find anything on the clip.
This may have been part of an earlier problem, I tried to use Window’s Media player to update the information on my clip so it can go also be listed in the proper album but it looks like it tried to add the songs to the clip so I ran out of space on the clip.
At least the clip is playing my songs but like before I have to scroll through the thing to find the artists.