Download NirCmd from here the x64 version:

Copy NirCMD to system32 on the machine and unblock the file

Create a folder somewhere to store the screenshots

Create a scheduled task

Select NirCMD as the program to start and add this argument:

loop 540 60000 savescreenshotfull “C:\downloads\scr~$currdate.MM_dd_yyyy$-~$currtime.HH_mm_ss$.png”

The above command means create 540 screenshots but wait 60 seconds between screenshots (9 hours)

edit the frequency of the command and the scheduled task as needed

Once Done you can create a slideshow from the pictures like so: