A small popup menu doesn't appear after holding the power button

A small popup menu doesn't appear after holding the power button

Problem: This is also one of the most often encountered Android problems. When you hold the power button for a few seconds, a small Phone options menu (like the one on the screenshot) will  or, at least, should appear.

This menu allows you to power off your phone, turn off or on airplane mode or restart your phone. However, in my previous phone (HTC Desire S) at some point this function simply stopped working and the phone wouldn't react to holding the power button.

Solution: This Android problem is a real pain in the neck. Unfortunately, restarting the phone or turning it off and on didn't help. The only thing that worked was restoring factory settings.
To do that, do go Settings > Backup & reset > Reset Phone. Before you do that, remember to backup your settings with either a third party app or use the default function also available under Backup & reset > Backup & restore.