i will try again
1. it knocks on the door. you see special unit from three sides entering the house. you leave the workstation and forget to press [windows] + l, so the station is not locked.
2. if activated, the screensaver starts after x minutes of inactivity and locks the station, so you have to enter your password to login. the account is locked.
screensaver activation starts not if a media player is running (suppresses screensaver while playing video, and sometimes also in audio mode). there are many possible reasons which prevents screensaver from activation.
now i am searching for a piece of software, which is able to
start an action (e.g. lock station)
if an action of me is missing (e.g. pressing [ctrl] + x or a mouse gesture)
for example, every 5 minutes it sounds a wav, so i know i have to press [ctrl] + x, if not the software locks the station.