I am trying to move music from my computer without syncing or loosing my iPhone music. When I change the manage music manually (which all of the forums say is the way to do it) I get a notice that says I will loose the existing songs!

Question

I have been with Apple from the 80's and have tried to flow with the changes, but seriously, this simply *****!
I am taking a class and have 2 songs that are on my macbookpro, I need to get them onto the phone WITHOUT deleting the rest of the songs already on the phone.   No! I dont want to erase the phone! and I also dont want the music on the phone to be moved to the computer because the computer is occasionally accessed by my students

Answer 1

Well, most of what we can tell you is already stated in the message you are getting.  A phone can only sync with one library at a time.  You have apparently synced your phone with a different iTunes library in the past, or changes have been made to this library so the phone no longer recognizes it as the library with which it was synced.  To know which you will have to provide the information.
If you bought them using the AppleID you use with this phone it may simply be easier to re-download them directly to the phone rather than sync them, though you will want to resolve that issue at some point.
Downloading (using iOS or computer) past purchases from the App Store, iBookstore, and iTunes Store - http://support.apple.com/kb/ht2519