If you hold in the power button for a bit it will shut off. Keep in mind that shutting off the system like that in the middle of updates may cause Windows not to load afterwards due to corrupt of missing files. But in your case with the system not making any progress that is the only option.
As stated, the best you can do is hard power it off and back on and hope for the best.
Sorry we have nothing more helpful, hopefully you at least had decent file backups as I give you a 75% chance that you will have to reinstall windows.