Weird changes to windows after turning PC on

Hello,

I have Windows 8.1 64 installed.
I turned my PC on today and I noticed some weird changes:

1. Wallpaper is changed to the default orange wallpaper.
2. Desktop settings are reset (icons visibility, screen saver, etc).
3. Apps in start menu disappeared (they are still installed, but no longer pinned).
4. If I sorted apps by date installed, I see that the following apps were installed today:
Store, PC Settings, Desktop, Camera, Photos, OneDrive, Application Verifier, Photo Gallery, Movie maker.
5. Folder called TEMP is created in C:\Users.
6. When I launch CMD it starts in C:\Users\TEMP.

The last thing I did was simply turning the PC off, and it turned off normally. No updates/installations were in progress.
No updates are newly installed (last update was a year ago).
Event logs don't show anything unusual.
No viruses detected.

Cheers.

 

It turned out that for some reason Windows created that temp user and logged me to it. I don't know why it did that.