This seems to happen most often to laptop owners. Desktop owners usually resort to pulling out the power plug, but you can’t do that with a laptop due to the battery.
There can be many reasons that cause a PC not to shutdown normally, but many people don’t realise that there is a “secret” way to force a computer to power off.
A quick word of warning: powering off in this way can lead to data loss, or even a non-starting Windows, as vital data can be either not be saved, or even corrupted… The chances of this happening can be minimised if you make sure the HDD light is off before you try this:
Press (and hold) the power button for about 5 seconds. That usually forces the computer to power off.
Note: you should rarely need to power off in this manner. If you need to do this often (or all the time), then there is something wrong, and you need to fix the cause of the problem.