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;

 {********************************}

 function GetNumberOfCDDrives: Byte;
 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
 Inc(Result);
 end;
 mask := mask shl 1;
 Inc(root[1]);
 end;
 end;

 procedure TForm1.Button1Click(Sender: TObject);
 begin
 Label1.Caption := IntToStr(GetNumCDDrives);
 end;