computer doesn't auto-shutdown

I use Win 10 Home Pro 64, 24g RAM, gigabyte mobo, SSD 1 TB, other usb drives. My computer has run reliably for some years. Lately I've noted that the preferences for Start/Stop/Sleep/Hibernate are not responding. I just want my machine to shut down or sleep after fifteen minutes. What's happened and is there a fix for it? Thanks.

Arthur

Have you recently installed a new program (or updated an older one) that may be active in the background? Activity could be keeping the computer awake. Maybe an antivirus that's always scanning the drive?


Also try temp unplugging or turning off any USB drives that may be running.