Sorry about the OT, but I hope this saves some people from sleepless nights:
One of the major problems that I had with VLC is that the monitor doesn’t go off afterward, even after closing VLC, which makes it harder to sleep. It took me a long time to find that VLC was the cause. A restart fixes the problem, but if you go to Control Panel–>Display–>Screen Saver tab, then click on “Power”, and then just click OK on everything, it fixes the problem without changing anything or having to restart. If you go to Control Panel–>Power Options, it doesn’t do anything. You have to use the Power button in Control Panel–>Display. You could also access “Display” by right clicking an empty area of the desktop and choosing “Properties”.
To stop VLC from disabling the screensaver altogether, go to Tools–>Preferences, then at the bottom left, look for “Show settings”, and click “All”. Now on the left, click on “Video”, then uncheck “Disable screensaver”.