Even that old machine would/should power down if you press and hold the power button for 4 seconds.

The issue has thousands of web pages about it so I won't duplicate prior ideas. Today if I don't spot the issue in a few minutes we reload the OS since troubleshooting costs skyrocket and the owner does not want to pay the usual 500+ bucks for a day of troubleshooting.

You bring up a good point. Did Microsoft blow it by not supply OS repair tools that actually work? It's like a car that an air filter failure means you replace the engine.