Определить букву CD-ROM

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;