The LabVIEW 7.1.1 Student Edition comes with 4 CD's. One of the CD's is a tutorial CD which does not contain a serial number. The other 3 CD's (Installation, Control Design & Sim Add-on, Signal and Image Processing Add-on) have serial numbers written on the CD - it specifically says, "Serial Number" just above the National Instruments logo.
Assuming your copy of LabVIEW 7.1.1 Student Edition is not pirated, finding the serial number should be easy.
-Danny