Hi Kevenle, and welcome to AF
I assume (from your post history) that you have a HTC One?
No, 50 minutes is too long. You did this update via the software updates menu, and your phone is unmodified (i.e. not rooted)? Just want to be sure we know the situation.
Try forcing a shutdown by pressing and holding the power button. I don't think you've got any other options.
See whether it will boot after that - probably not, but you never know. If not, reboot again but this time press and hold the volume down key when it starts to boot. That will get you to the bootloader screen. From there you have 2 options:
1) if you select recovery you can try wiping cache or doing a factory reset. If the problem is incompatible or corrupt data this should fix it. I've never used the stock recovery on the One (I'm rooted and use a custom recovery), but generally with HTC recovery you need to press some combination of power and volume keys to bring up the menu when you are in the recovery screen (typically black with a red triangle).
2) if it's the actual system software that is corrupt you should be able to re-flash the phone using a ROM Update Utility package. To run this you need to download the package to a PC, put the phone in fastboot mode (select this from the bootloader menu), connect to PC and run the RUU (a Windows .exe) on the PC.
The trick is to find the right RUU for your phone. I'm typing this on my phone on my way to work, so can't easily search for one at the moment, but maybe someone else will have a suggestion.
In the worst case, since you've done nothing and an official update did this, it's covered by warranty and you can just get it fixed by a service centre (which will just reflash it as described). It's just quicker if you can fix it yourself.