I had a system that did this and everytime
the phone rang the system would startup by
itself, go into the bios and check power
options, PCIME settings should be disabled,
that's if you have a modem connected.
Or might be your lan port powering the
system up
"Beverly Howard [Ms-MVP/MobileDev]"
insuffient data captain...
how are you shutting down the computer?...
step by step and what do the dialogue
boxes say?... for example, does step 3
possibly say "restart" rather than
"shutdown?"
If you press and hold the power button
just as the computer restarts, it should
power down again and stay powered off...
if this works, I would suspect foul play.
If your action says "shut down" and the
power turns off (fans stop, hard drive is
quiet) but it still restarts... try the
following...
After you issue the shutdown command and
before it powers down, disconnect
keyboard, mouse and network cable...
If it still powers down and restarts,
there is some type of hardware issue with
the cpu or malicious software... tech
time... for example, a virus might be
directing a restart for zombie purposes.
You might look at the bios to see if there
are any "power up on..." settings.
Beverly Howard [MS MVP-Mobile Devices]