Int 21 Fn 6262  - Envlock - Installation Check                             [U]

   AX = 6262h
   SI = 1994h

Return: AX = 1994h if installed
       ES = ENVLOCK's resident segment

Notes: to deactivate ENVLOCK, zero out the byte at ES:[0102h]
Program: ENVLOCK is a TSR by Alexander Yanovsky (aka PC Hawk) that forces
     other TSRs to deallocate their environment when they stay resident