Как узнать букву CD-ROM?

Code:

procedure TForm1.Button1Click(Sender: TObject);

var

w: dword;

Root: string;

i: integer;

begin

w := GetLogicalDrives;

Root := '#:\';

for i := 0 to 25 do

begin

   Root[1] := Char(Ord('A') + i);

   if (W and (1 shl i)) > 0 then

     if GetDriveType(Pchar(Root)) = DRIVE_CDROM then

       Form1.Label1.Caption := Root;

end;

end;