Vista - Power Settings reset problem

My computer has been resetting its power settings at random points, and it's
getting annoying. I've had to put them back more than a dozen times in the
last week. It's definitely saves them when I shut down, but once in awhile,
the computer freezes up, or just goes to sleep, and the next time I start up
the setting have been reset (to really bad settings too...I don't want to
hibernate after 5 minutes of inactivity). Anyone know how to fix this? Or if
it is related to any of the recent updates?

My computer is using Windows Vista Business.

Allo? Anybody there who can help? Well, here's some more details if they
could be of use.

My power settings only seem to change when the computer is on battery...when
on AC, I can do a whole bunch of random power things, and they stay the same.
What's more, the setting never go back to the default settings, they go to
something completely random and useless (always require password log in, 5
minutes to sleep AND hard drive shut off, 20 minutes to hibernation...kinda
short for a person who repeatedly has to put his comp to sleep just to walk
between classes, only to have to take 5 more minutes to wait for it to come
out of an unexpected hibernation).

It's not only annoying, since having to log in everytime means that the
display automatically takes 30 seconds to flicker my desktop to portrait
orientation, but I just recently had to do a complete system restore because
my computer couldn't recover properly from its 5th straight involuntary
hibernation that day.

I have done every virus scan, spyware scan, and other scan that I can
possibly think of, and nothing of the kind has shown up. That leaves one of
the Vista updates to be the culprit, or possibly my screensaver, although it
seems to be trying to do the opposite thing when my computer is on AC (and
who can blame a screensaver that just has you float serenely over the
ocean...). Any ideas? Please?

Oh, and if you can figure out how to prevent any kind of screen flipping of
any kind (display flipping from landscape to portrait just...well, just
because...I dunno), that would be great too. And maybe the whole duplicate
user log in buttons thing too. =)