Code:

function LastInput: DWord;

var

LInput: TLastInputInfo;

begin

LInput.cbSize := SizeOf(TLastInputInfo);

GetLastInputInfo(LInput);

Result := GetTickCount - LInput.dwTime;

end;

//Example:

procedure TForm1.Timer1Timer(Sender: TObject);

begin

Label1.Caption := Format('System Idle since %d ms', [LastInput]);

end;

// The GetLastInputInfo function retrieves the time

// of the last input event.

// Minimum operating systems: Windows 2000