Windows Update Issue. Cannot Boot Laptop

[msrez]

I tried to perform a Windows update (Windows 10) on my Pavillion x2 Detachable yesterday. I downloaded the update .ISO onto an external USB drive as the internal storage on the laptop is only 32GB. The update proceeded and I left it updating for a few hours, only when I returned it was stuck in a loop of saying "Undoing changes made to your computer...". After a while it reboots, the HP logo appears on screen and it returns to this screen again (black background, white text). If I remove the USB drive and reboot I get the message "Please insert the external storage media and press OK". This message just re-appears as soon as I press OK. If I re-attach the USB drive then it returns to the "Undoing changes" loop. I have since spoken to Microsoft support and they have tried directing me to get the machine into Safe Mode by pressing F8 on boot, and several other combinations but they're unsure of the shortcuts HP uses (as am I), so I'm at a loss at what to try next. I'm happy to do a fresh install of Windows but I can't get to that stage either. Any help would be much appreciated.

[WAWood]

@msrez 

Some of these lightweight laptops come with really SMALL "disk drives -- of 32GB or so, and that is insufficient to do Windows Updates without running out of space.

From your description, it sounds like this is what happened to you -- and this is a Windows Update loop that will keep failing over and over until you get fed up and turn off the PC. 

If your PC is a 2016 model or newer, you should see if you can make a bootable USB recovery drive using the HP cloud recovery tool on a working PC.

The recovery drive can then be used to install Win10 and the HP drivers and utilities that originally came with your PC.

Here is the link: https://support.hp.com/us-en/document/c06162205

NOW, if that works -- the next issue is that Windows Update will start downloading and installing updates to bring your PC up to the present version -- and that's going to fill up the "disk drive". 

So, when that happens, read below about stuff you can do to free up disk space:

http://www.tenforums.com/tutorials/3012-disk-cleanup-open-use-windows-10-a.html
http://winaero.com/blog/how-to-clean-up-winsxs-folder-in-windows-10/

Also, the community Win10 Forums has the following suggestions:
https://www.tenforums.com/tutorials/83441-free-up-drive-space-windows-10-a.html

In addition, I have found the utility Cleanmgr+ to have LOTS of options for removing Windows junk, including log files. I use it practically every day. You can get it from here:
https://www.mirinsoft.com/cleanmgrplus

Also, there is a freeware app known as Wise Disk Cleaner. I use it every day to get rid of junk files: https://www.wisecleaner.com/wise-disk-cleaner.html