INT 2F U - NORTON UTILITIES 5.0+ TSRs - DISABLE
        AX = FE02h
        DI = 4E55h ("NU")
        SI = TSR identifier (see AX=FE00h)
Return: SI = TSR reply (lowercase version of entry SI, i.e. SI OR 2020h)
        AX = status
            0004h successful (DISKMON, FILESAVE)
            FE00h successful (NCACHE-x, DISKREET)
Note:   (see AX=FE01h)
SeeAlso: AX=FE01h