Go into the Power Options control panel and under Advanced tab, choose "When I press the power button on my computer" and select "Shut down." When you press and release the power button that turns the computer on, it will also shut the machine down.
Forcing a shutdown is going to catch up with you sooner or later and this is a very elegant solution.
I agree wholeheartedly and this is exactly how i set mine up.
I used an old two pin connector i had taken from a dead pc case, and spliced some long wires onto it.
i plugged it into the power button place on the motherboard and then hooked that up to an arcade pushbutton on the very top of my cabinet.
then i configured windows to shut down when you press the power button, as previously mentioned.
It works flawlessly and always gets a proper shutdown.
one more thing i have done. when your pc does properly shut down, you also want the Monitor and the Marquee to turn off too.
Any DpSt or Dpdt 120v AC Relay put in a relay socket so you can change it as it ages, that has a 12Vdc coil will work for this. Just Wire the 120v secondarys in between your power source, and your power strip. Wire one pin on the Coil up to one of the disk drive connectors on your computer power supply to the Yellow and wire the second one to one of the Black wires. Plug all of your 120v stuff into the power strip, and off you go.
everytime the Pc power supply is on, the Disk drive connector will have power, it will activate the coil in the relay, and act as a switch for whatever 120V line level things you have plugged into the power strip.
problem solved.
this is a total solution between these two methods.
Proper shutdown of your computer, and simultaneous shutdown of your entire arcade cabinet with one push of a button.