INT 2F - NDOS v4.0+ - KSTACK.COM - INSTALLATION CHECK                           
	AX = E44Fh
	BX = 0000h
Return: AX = 44EEh if installed
Program: NDOS is a version of 4DOS licensed to Symantec for inclusion in the
	  Norton Utilities
Note:	this function is also supported by ANSIPLUS v3.01+ and K3PLUS v6.20+,
	  which emulate the 4DOS and NDOS keystack
SeeAlso: AX=D44Fh/BX=0000h,AX=E44Fh/BX=0001h