A batch that is like a computer password, maybe you could stick it in autoexec.exe and make it run off startup?

@Echo off
echo Enter password then [F6] and then smack the [Enter] key real hard!
prompt $e[30m
echo on
echo off
copy con password.dat>nul
prompt $e[0m
echo on
echo off
cls
copy password.set+password.dat password.bat>nul
call password.bat
if '%password%==qwerty goto done
echo Incorrect, you are not trying to break into my pc are you?
choice /t:y,3
if errorlevel 2 goto next
:next
erase password.bat
erase password.dat
:hello
cls
echo Turn off PC
goto hello
:done
erase password.dat
erase password.bat
set password=qwerty
prompt $p$g