Windows Media Player playlists

Hi.
I have just started using WindowsMedia Player 11 to play some DTS files that wouldn't play in Media Monkey but they wouldn't all go into the WMP library for some reason. To get round it I made playlists of the seven albums and that worked fine. The only little niggle is that I have ended up with a category called Recent Playlists which contains five of the seven albums and also a category displayed on the same page called All Playlists which contains all seven albums.
I would like to delete the Recent Playlists category all together for good as I have no use for it and it is cluttering the page.
I have tried clearing the history in Options but to no avail. Any help would be greatly appreciated.
Regards Alex