Category: <b>virus/antivirus</b>
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<pre><b>INT 21 - VIRUS - "Tremor" - INSTALLATION CHECK</b>

	AX = F1E9h
Return: AX = installation state
	    CADEh installed, and calling program is infected
	    F100h not installed (normal DOS return value)
	    else  installed, but calling program is not infected
SeeAlso: AH=F1h"VIRUS",AX=F2AAh
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