For no apparent reason, my Windows 10 (1903) system has forgotten how to shutdown or sleep. If I try to sleep, the screens go black for a second, and then appear again without change. If I try shutdown from the start menu, it pretends as if it is going to shutdown, but then leaves me at the login screen. I have tried a few things from googling, but the only way I have found so far to shutdown (other than the long power button) is “shutdown /p” from an administrator command prompt.
Any ideas?