I can navigate as far as C:\Users\User_Name but then cannot see Appdata.
You may need to change the settings on your system to hide system folders.

this leaves with the problem of not being able to delete.
Reboot your machine and do not start any applications. Make sure that all Office applications are closed if they autostart on system boot.

Then delete the files.

If that does not help, start the computer in Safe Mode, then delete the files.