Every so often, I find my system a little slow even tho' I'm not doing much. When I look ta what's going on via Task Manager, I sometime s find Word or Powerpoint processes running & taking 50-60 % CPU when I'm not even using them. I can kill them easily enough but why are they starting for no reason?
Good that you used Task Manager to find out what was running.
Can you tell if some particular document or presentation is/was opened?
Go into Event Viewer and see if you can find more details regarding what is running along with when and why they started.
Could be some upgrade/update - or some background launch via browsing....
I edit Word and Powerpoint files very regularly but the rogue tasks appear much less frequently which makes me think they aren't related to my recent edit of either type of file. They never appear together.