INT 2F - F-PROT v1.x only - F-POPUP.EXE
        AX = 4653h
        CX = 0004h
        BX = subfunction
            0000h  installation check
                Return: AX = FFFFh
            0001h  uninstall
                Return: AX,BX,ES destroyed
            0002h  disable (v1.08 and below only)
                   display message (v1.14+)
                        other registers: ???
            0003h  enable (v1.08 and below only)
                   display message (v1.14+)
                        other registers: ???
                        Return: AX = key pressed by user
Note:   F-POPUP is part of the F-PROT virus/trojan protection package by
          Fridrik Skulason
SeeAlso: AX=4653h/CX=0005h,AX=CA00h