INT 2F - License Service API - INSTALLATION CHECK
        AX = 7000h
        CX = license server index (0000h to 001Fh)
Return: AL = status
            00h not installed
            FFh installed
Notes:  The License Service API is being maintained by Microsoft but is being
          supported by a large number of companies including Apple, Banyan,
          DEC, HP, Lotus, Microsoft, Novell, Software Publishers Association,
          and Wordperfect (not a complete list!)
        Each license service provider must search for the next free index
          slot to use
SeeAlso: AX=7003h,AX=7004h,AX=7005h