There are two ways to reboot your computer when it's totally stuck:
  1. With the Power Button
  2. With the Power Cord
To use the power button, simply find it on your computer, press it in and hold it for 6 full seconds and then release it. This will power off your computer. Then wait 5 full seconds and press it again holding it in for only 1 second before releasing it to power it back on again.

To use the power cord method, you need to make sure your computer doesn't have a built-in battery - laptops usually do and therefore do not work with this method without first removing the battery as well. If you know you don't have a built-in battery on your computer, just unplug the power cord, wait 5 full seconds, and then plug it back in again. Wait 5 more seconds and then press the power button, holding it in for only 1 second before releasing it. This will turn your computer back on again.