[[escafandra]]

void DirList(String Dir, TStrings* Salida)
{
    TSearchRec sr;
    if(!FindFirst(Dir + "\\*.*", faAnyFile, sr))
    do{
       if(sr.Name != "." && sr.Name != ".."){
          if(sr.Attr & faDirectory)
             DirList(Dir + "\\" + sr.Name, Salida);
          else
             Salida->Add(Dir + "\\" + sr.Name);
       }
    } while (!FindNext(sr));
    FindClose(sr);
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{
   DirList("C:\\Archivos de programa", ListBox1->Items);
}

Saludos.