Deleteting songs

If you are using windows media player, whatever is on your sync lists will be added to you ilo and what is on your ilo that is not on your synch list will be deleted from your ilo, when you udate your sync.
For example say on your ilo you have only one album from oh I don't know lets say....Beefheart and on your synch list you have the Monkey's greatest hits and five different re-mixes of the Macerana. When you sync up, the WMP should take the Beefheart off you ilo and put on the Monkey's and the remixes. Despite your wierd taste in music, it should do all this for you.
Think of your ilo as just a player and the WMP as the program that takes the music on and off the ilo.