Select CRT_Screensaver as your system screensaver, that you can see some changes of desktop windows when screensaver is running. Such as: foreground windows, task button, Notification area. Maybe you have disabled the screensaver, Because you don't want to miss some important message on the screen. Now you can try this screensaver, You can see desktop windows when screensaver is running by settings, neglect neither screensaver energy saving nor work.
||Free to try
Windows Server 2008,