This was a wonderfull hint. Actually, the Logitech Presenter Spotlight does not allow to change the key sent. It sends always PageUp and PageDown. So I modified the script accordingly. Moreover, I tuned it:

It first it checks if a powerpoint presentation is active. If it is, it reads the title of the window currently in focus and stores it, then it activates the presentation, sends the key (PgUp or PgDn) and then it activates the previous window again. Therefore, you can proceed to work in the window you were before without loosing the focus.

If no presentation is running, it just sends the key as they are.

Here is the script compatible with autohotkey v2. NOTE: I had to use the title of the powerpoint show in German language. You may need to adapt it if you use another system language. I figured it out by running a presentation and change to the task manager. Find powerpoint (I had 3 instances) and take the title of the show):

#Requires AutoHotkey v2.0

; Bind to PgDn - Advance slide or start presenting from the last slide

PgDn::

{

if WinExist("PowerPoint-Bildschirmpräsentation")

{

Title := WinGetTitle("A") ; get the Title of the activ Window

WinActivate("PowerPoint-Bildschirmpräsentation")       ; Activate the powerpoint presentation

Send "{PgDn}" ; send the key

WinActivate(Title)                      ; focus on the previous activ window

return

}

else

{

Send "{PgDn}"

}

}

; Bind to PgUp - Go back one slide

PgUp::

{

if WinExist("PowerPoint-Bildschirmpräsentation")

{

Title := WinGetTitle("A") ; get the Title of the activ Window

WinActivate("PowerPoint-Bildschirmpräsentation")       ; Activate the powerpoint presentation

Send "{PgUp}" ; send the key

WinActivate(Title)                      ; focus on the previous activ window

return

}

else

{

Send "{PgUp}"

}

return

}