Another day, another try at hearing the meanwhile familiar >click< when hitting [PrtScr] after a reboot. Without opening captor at first. Can´t get it to work. No way:
I open Captor by clicking on the big icon on the desktop. Captor resides minimized in the notification area. Left click on the upwards arrow: Right click on the small captor icon. Left click preferences, ensure that "start with windows" is on. Repeat this procedure several times. Don´t know how often. But then after the n-th attempt, the left click on preferences makes the captor window to vanish.  No matter. It´s OK. "start with windows" is on anyway, I presume.  Open and run captor as admin: Allow changes: Yes: >Edit  >Preferences  "start with windows" is still on: [Apply] [Accept] [Close]: Check Autostart in Task-Manager: ScreenshotCaptor is activated. Reboot: [...]: No >click<: No Icon in the notifcation area. Disappointed. Do I expect too much?

Halt, bevor ihr euch schlafen legt, muss ich dann permanent den ScreenshotCaptor mit Admin-Rechten starten. Also immer Admin sein und bleiben?

I found that. Thx. But I can´t find what is shown in ScreenshotCaptor Help. A view with a title bar (white letters on blue background: "Screenshot Captor Options") as here.

Screenshot of ScreenshotCaptor Help, not of ScreenshotCaptor.