Control Panel settings not saving.

I hope this is an easy one for you, cause I can’t figure it out 🙂 I am not sure when this started, but here goes… When I make changes in Control Panel for things like screen savers, themes, etc, I can apply them and they will stay in place UNTILyou reboot. Then the settings revert to what you had BEFORE you changed them. Any idea what is going on?