Error 0xc00000e9 is usually caused by a failing or a bad hard drive.
- see if any of the fixes here help: https://appuals.com/how-to-fix-error-0xc00000e9-on-windows-7-8-and-10/
long windows update sounds like a version update, did it restart PC a few times during process? If it lose power during this process it could be a broken install. Is there anything on PC you need to save?
On another PC, download the
Windows 10 media creation tool and use it to make a win 10 installer on USB
change boot order so USB is first, hdd second
boot from installer
on screen after languages, choose repair this pc, not install.
choose troubleshoot
choose advanced
choose command prompt
type
notepad and press enter (will open notepad)
go to file/open and will open file explorer, copy anything you need to keep onto USB or another hdd (if applicable)
Once you copied everything off you need to save, I would do a fresh install using the USB
boot from installer
follow this guide:
http://www.tenforums.com/tutorials/1950-windows-10-clean-install.html
when you reach the screen asking for licence, click "I don't have a key" and win 10 will continue to install and reactivate once finished
On the screen where you choose where to install win 10, if it gives you an error about GPT drives, delete all the partitions on the hdd and press next. If it still gives error, cancel out of the installer and restart PC and start installer again, it will accept next on that screen this time (some PC just need a restart here)