This will echo the rename commands to the screen, so if it does what you want then remove the echo to make it work.
Filenames with !
characters will not be renamed.
@echo off
setlocal enabledelayedexpansion
for /d /r %%a in (*) do (
set n=0
pushd "%%a"
for /f "delims=" %%b in (' dir /b /a-d 2^>nul ') do (
set /a n=n+1
set num=0000!n!
echo ren "%%b" "%%~nxa!num:~-4!%%~xb"
)
popd
)
pause