- inside my little head I answered and thanked you long ago, but now I realize that I wrote nothing! Sorry!!

Yes, of course I've tried it, and it works fine.
There are some behaviours that I don't fully understand, when I have a window of a kind open, but for the time being I have simply minimized all windows before I press the hotkey and only then maximize the IrfanView window, to see where the center is. Within this frame, ShowScreenCenter works just perfect.
Thanks, lanux

Show Center of monitor screen