INT 2F - DOS 3.3+ GRAFTABL.COM - INSTALLATION CHECK                             
	AX = B000h
Return: AL = status
	    00h not installed, OK to install
	    01h not installed, not OK to install
	    FFh installed
Notes:	called by DISPLAY.SYS
	documented for DOS 5.0, but undocumentedInformation about a product which is not publicly available from the manufacturer, and must be determined by reverse-engineering (disassembly, trial-and-error, etc.).	 Undocumented information tends to change -- often dramatically -- between successive revisions of a product, since the manufacturer has no obligation to maintain compatibility in behavior which is not explicitly stated. in prior versions
SeeAlso: AX=2300h,AX=2E00h,AX=B001h