The only thing actually 'running' at that point in time in the OS. ie.
various services.
So if you would want to set anything at that point in time, you would have
to devise a way to have something like a registry 'update' automatically
running (unattended) as a service.
And then still, AFAIK these settings are user-related (contained in
HKCU\Desktop\PowerCfg), so for what user would you set them?
I'm not aware of locations in the registry that would relate to the system
itself.
george