var DriveType: UInt;
DriveType := GetDriveType(PChar('F:\'));
if DriveType = DRIVE_CDROM then ShowMessage('Сидюк');

function GetFirstCDROM: string;

{возвращает букву 1-го привода CD-ROM или пустую строку}

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

  begin

  Result := Root[1];

  exit;

  end;

 end;

 Result := '';

end;

function GetFirstCDROMDrive: char;
 var
  drivemap, mask: DWORD;
  i: integer;
  root: string;
 begin
  Result := #0;
  root := 'A:\';
  drivemap := GetLogicalDrives;
  mask := 1;
  for i := 1 to 32 do
  begin
  if (mask and drivemap) <> 0 then
  if GetDriveType(PChar(root)) = DRIVE_CDROM then
  begin
  Result := root[1];
  Break;
  end;
  mask := mask shl 1;
  Inc(root[1]);
  end;
 end;
 procedure TForm1.Button2Click(Sender: TObject);
 begin
  ShowMessage(GetFirstCDROMDrive);
 end;

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;