Function GetCDList : String; 
Var 
   I    : Integer; 
  Drives: Integer; 
  Tmp   : String; 
begin 
Drives := GetLogicalDrives; 
  Result := ''; 
// units A=0 to el Z=25 
  For I := 0 To 25 Do 
    If (((1 Shl I) And Drives)<>0) Then 
    Begin 
      Tmp := Char(65 I) ':\'; 
      If (GetDriveType(PChar(Tmp))=DRIVE_CDROM) Then 
                                   Result := Result Char(65 I); 
     End; 
End;