INT 2F - TBSCANX - INSTALLATION CHECK                                           
	AX = CA00h
	BX = 5442h ('TB')
Return: AL = state
	    00h not installed
	    FFh installed
		BX = 7462h ('tb') if BX was 5442h on entry
Program: TBSCANX is a resident virusA program which attaches itself to other programs for the purpose of duplicating itself.	Viruses often (but not always) contain harmful code which is triggered by some event, after a certain number of reproductions, or on a specific date.  See also worm. scanning module by Frans Veldman.
Notes:	programs may perform virusA program which attaches itself to other programs for the purpose of duplicating itself.	Viruses often (but not always) contain harmful code which is triggered by some event, after a certain number of reproductions, or on a specific date.  See also worm. checks on themselves, other program files,
	  or their data files by invoking the TBSCANX API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes..
	current versions of TBScanX don't actually check the value of BX
SeeAlso: AX=4653h/CX=0002h,AX=4653h/CX=0007h,AX=C900h