[delphi.com.ar]

No se si tomará las de DVD, sino tendrías que fijarte que es lo que te da DriveType:

Código Delphi [-]
var
  dwDrives: set of 0..25;
  iDrive: Integer;
  sDriveName: string;
begin
  DWORD(dwDrives) := GetLogicalDrives;
  for iDrive := 0 to 25 do
  begin
    sDriveName := Char(65 + iDrive) + ':';
    if (iDrive in dwDrives) and (GetDriveType(PChar(sDriveName)) = DRIVE_CDROM) then
      Memo1.Lines.Add(sDriveName);
  end;