INT 2F - ANARKEY.COM - INSTALLATION CHECK
        AX = E300h
Return: AL = 00h not installed
             FEh if installed but suspended (v3.0+)
             FFh installed
Notes:  ANARKEY.COM is a commandline recall program by Steven Calwas
        E3h is the default function number, but can be set to any value from
          C0h to FFh
SeeAlso: AX=E302h,AX=E303h,AX=E304h,AX=E305h,AX=E306h,AX=E307h