I fixed it! Just for other's info, it seemed to be related to the system
drivers for the ACPI functions. I went to Device Manager and opened the
properties for the 3 system devices that were related to ACPI. I ran a
driver update on all 3. No visible result but it went thru the process.
Then I noticed the Display device had an exlamation symbol on it so I opened
it and it said the driver needed updating. So I ran a driver update on it
also. It corrected itself without any external search so I'm not sure why it
was needed update but it corrected itself. After all this the standby
function returned. Not sure whether it was the driver fixes on the ACPI
devices or the display driver but one of them fixed it.