Desktop went t/u, unable to save info, bought laptop and installed itunes, now when trying to sync itunes says I am conected with more than one library. I can't do anything. Please Help

Our desktop went t/u and was not able to save any music files except what is on ipods. Bought laptop and installed itunes. Was able to load music from wifes "classic" that was bought through itunes but my "itouch" w/music not purchased will not sync. Itunes says I am connected to more that one "Library" and cannot sync. Anyone else ever hear of this happening?

Thanks James