I FINALLY got around to opening the box--to put in some new RAM.
While I was in the box, I tried disconnecting the power switch
connector from the motherboard while Vista was running and then tried
a shutdown. No luck--restarted as always! I then tried the same with
the "restart sw" connector and still no luck. Furthermore, when I
took it back to the retailer, one of their techies said he was able to
do a shutdown successfully from BIOS.
First appreciate how a power supply system gets turned off. The
operating system must understand what power supply controller is being
used AND therefore how to talk to it. Things such as removing power
switch were recommended on wild speculation; not based upon how
hardware works.
Second, if the OS does not know how to talk to that power supply
controller, then it cannot command power off. BIOS, obviously, would
know how to issue those same commands.
So your objective is to install the appropriate software (probably
in HAL) for that particular motherboard. The rub. You cannot do
that. That information is simply withheld from or completely
mysterious to most techs. Sometimes that software for that
motherboard does not even exist. That software would be unique to a
motherboard chip set AND should be available from motherboard
manufacturer. That manufacturer should have provided correct software
for Microsoft to include in Vista. Often information is not
available unless you make yourself enough of a pain. Most motherboard
manufacturers are dealing with people who don't know how electricity
works, did not even know about the power supply controller, and did
not know why the power switch would be completely irrelevant. Better
from them is to say nothing; claim that information is not available.
I can only point you in the right direction. BIOS could power off
the computer suggesting computer hardware can talk to power supply
controller AND power supply controller can turn off power supply.
That implies Windows has installed the wrong software for your power
supply controller.