If you loaded it "on top of" LabVIEW 2015 (meaning you loaded it on a machine that already has a valid license and is activated), then if your license has been renewed (i.e. your school had purchased the license for 2016), it should "find" the old license and install the new software under the old license. Once that is done, you will be asked to Activate, which should succeed if the license is valid.
It has worked that way for me except for one year when NI "lost" our P.O. We got it straightened out ...
Bob Schor
