@echo off
set T=%SystemDrive%\TEMP
set DPARTSCRIPT=%T%\diskpart.txt

echo ####### %0 #######

> %DPARTSCRIPT% (
  @echo.select disk 0
  @echo.select partition 2
  @echo.remove all dismount
  @echo.exit
  @echo.
)

diskpart /s %DPARTSCRIPT%
if %ERRORLEVEL% NEQ 0 (
  echo ERROR: while removing the drive letter!
  del /F %DPARTSCRIPT% 1>nul 2>nul
  exit /b
)
echo Drive letter removed.

rem cleanup ...
del /F %DPARTSCRIPT% 1>nul 2>nul

echo ####### %0 #######