Windows won't go into standby mode or hibernate after a long period of inactivity.....maybe one fix

Docster

Your computer is set to Portable/Laptop, off monitor aft 15 min, off
harddrive aft
20 min and sys standby aft 20 min. It use to go into standby and all you had
to do was hit the keyboard, move the mouse or bump the computer and it would
wake up...........................then one day it all just stopped. The
monitor still goes into standby but that's it..............not he computer.
I know this is an old problem. WinXP SP3.

I have been hacking around with this for about 3 years and this morning I
think I stumbled on to something that might be a help to others. It worked
for me and I am smiling again. After many years of use my computer would
faithfully go into standby and wakeup with the movement of the mouse or
activity on the keyboard, then one day it just quit. Well here is what I
found:
Using the following string executed in "Run" (%windir%\System32\rundll32.exe
powrprof.dll,SetSuspendState) I got the following message, "The device
driver for the 'American Power Conversion USB UPS" device is preventing the
machine from entering standby. Please close all applications and try again.
If the problem persist, you may need to update the driver".

I uninstalled the APC Power Chute Personal Edition 3.0.2 and that did not
fix the problem, I then went into Device Manager and
deleted APC UPS under Batteries and this did not fix the problem as this
reference has and requires no drivers.
The next thing I did was to delete "American Power Conversion USB UPS under
"Human Interface Devices".
When I completed the deletion of the American Power Conversation USB UPS
under "Human Interface Devices" and ran the string again the computer went
into Standby and woke up by mouse or keyboard movement as it had prior to
the disruption.
I then reinstalled the APC Power Chute Personal Edition 3.0.2 software and
the computer still performed as it was supposed to.
Apparently the drivers for the "American Power Conversation USB UPS under
"Human Interface Devices" must have gotten corrupted up and when I deleted
them they were forced to rewrite.
This is the first fix for me in this long and aggravating as well as
annoying problem. Hope it helps someone else.
If you only want it to go into Standby make sure you uncheck Hibernate on
the Hibernate tag in device manager.

This is a jpg of what my health drivers list looks like for "American Power
Conversation USB UPS under "Human Interface Devices"