a easy way to protect file in windows

put your important file in specific folder,Drag and drop the folder into the following batch file or you can put two batch files in "%appdata%\Microsoft\Windows\SendTo",then only right click and sendto lock or unlock

@echo off
rem lock the folder
%1 mshta vbscript:CreateObject("Shell.Application").ShellExecute("cmd.exe","/c %~s0 ::","","runas",1)(window.close)&&exit
cd /d "%~dp0"
icacls %1 /inheritance:r /t /c
icacls %1 /setowner %username% /t /c
icacls %1 /remove administrators /t /c
icacls %1 /remove system /t /c
icacls %1 /deny %username%:(OI)(CI)F /t /c
exit

@echo off
rem unlock the folder
%1 mshta vbscript:CreateObject("Shell.Application").ShellExecute("cmd.exe","/c %~s0 ::","","runas",1)(window.close)&&exit
cd /d "%~dp0"
icacls %1 /setowner %username% /t /c
icacls %1 /grant %username%:(OI)(CI)F /t /c
icacls %1 /inheritance:e /t /c
exit