>>329
set "a=D:\comp" & set "b=D:\compopen"
setlocal enabledelayedexpansion
for /L %%i in (4,1,1000) do if "!a:~%%i,1!"=="" set "c=%%i" & goto x
:x
endlocal & set "c=%c%"
for /r "%a%" %%i in (*.zip *.rar) do set "d=%%~dpni" & set "e=%%~i" & call :y
goto :eof
:y
setlocal enabledelayedexpansion
7z x -o"!b!!d:~%c%!" "!e!"