To change the properties of the screensaver, simply go to Windows directory and look for SCR files. The screensavers are copied in that location or if you have an executable file, right click it then go to Properties and tick the Run as Administrator. Some applications require exclusive access to system resources and since the SCR is placed on a system partition where Windows is installed, you will need permissions. You can give permissions to other users as well. Log in with Administrator, then right click the EXE or SCR and go to Properties > Security. Select the user and then change its properties.
