This is useful, if for example, if you watch a YouTube video and don't want to be interrupted by the screensaver, just run the program and add the word YouTube. Any window containing the text YouTube will trigger the application and prevent the screensaver or other power saving options.
It does this simply by simulating a key press every minute (shift key). Using this program is quite simple. Download and install the program. Run it (it will sits on the system tray) and add a text (or texts) (e.g. YouTube) and click OK to save.
You can disable the program (also from the auto startup lists of Windows) by removing the check marks next to ‘Enable Anti screensaver’.