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Disable F8 on startup

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Kurt Riechers

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Feb 2, 2001, 4:57:20 PM2/2/01
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Does anyone know how (or if) I can disable the startup options menu that you
get when you press F8 at startup on Windows 2000 Pro? I need to lock it down
from end users.


Alex Meaden

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Feb 4, 2001, 5:15:06 PM2/4/01
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Break the F8 key by levering it out.

"Kurt Riechers" <krie...@apl.org> wrote in message
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Michael J. Reynolds

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Mar 14, 2001, 5:13:31 PM3/14/01
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I got it! I needed the same thing, did some spelunking and found that ntldr
does the F8 checking & displays the troubleshooting menu. Since ntldr is
pretty small and can only use BIOS INT 16 for keyboard input, it was pretty
easy to look amongst all the INT 16 (keyboard handler) byte sequences in
there (there were only three). I found this one at offset 085A:

MOV AX,0100
INT 16 ;Checks if keystroke waiting in buffer, ZF=0 if yes, ZF=1 if no
JNE 09 ;Jump ahead nine bytes if ZF=0

By just replacing the JNE 09 with three NOP's (no op, byte code 90), I
disabled execution of the keyboard input handling, so no more response to F8
key press. If you want to check for yourself, load ntldr into your assembly
editor and search for "CD 16" hex string. You'll find three; this one's the
second.

If you don't want to fuss with doing yourself, I've put a copy of my ntldr
on our ftp site at skykomish.lib.washington.edu in the "Public" folder with
the name "ntldrNOF8" (log on as "anonymous"). In this version, I also
replaced the "press f8 for troubleshooting" text (found at bottom of ntldr)
with <space> characters so that users don't see the F8 prompt.

Mike Reynolds
Univ of Washington

"Kurt Riechers" <krie...@apl.org> wrote in message
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