

procedure TForm1.Button1Click(Sender: TObject);
var
  memory: TMemoryStatus;
begin
  memory.dwLength := SizeOf(memory);
  GlobalMemoryStatus(memory);
  ShowMessage('Total memory: ' +
              IntToStr(memory.dwTotalPhys) + ' Bytes');
  ShowMessage('Available memory: ' +
              IntToStr(memory.dwAvailPhys) + ' Bytes');
end;