Int 2F Fn 4653  - F-prot V2.x - Virstop - Enable/disable Bootsector Read   [-]

   AX = 4653h ('FS')
   CX = 0007h
   BL = new state of bootsector checking (01h = disabled)
Program: VIRSTOP is the resident virus-checker from Fridrik Skulason's F-PROT
     virus/trojan protection package