Problem with Playlists

[2wiSteD]

I've finally gotten one of those FM transmitters so I can use my V+ in my car. Since I've gotten and nearly filled it, I've gotten a new computer. Last night I 'shuffled' the music with WMP11. From what I understand, that deletes all music on your player, and puts the music in your current WMP library into your player. My problem is when I try to sync my one, main playlist. When I drag it over to sync, it says it's filled. It's like it's wanting to sync the playlist file AND all the music in the list (over 100).

Am I going to have to like.. format this thing and resync? If that's not what 'shuffling' is, what is it?

Edit: Might I add that all.. most.. of the music I have on this computer was directly transferred from the old computer.