WriteEmptyProfileString("%TEMP%\WriteEmptyProfileString.ini","TestSection","TestKey")

function WriteEmptyProfileString($ini,$section,$key)
  $error=0
  $=writeprofilestring($ini,$section,$key,@CRLF+$key+"=")
  if @error
    $error=@error
  else
    $=writeprofilestring($ini,$section,$key)
    if @error
      $error=$error+@error*1000
    endif
  endif
  $writeemptyprofilestring=$error
endfunction

$=WriteProfileString('.\test.ini','Section','Key','""')