Sounds to me like a version update hasn't worked. That would be only type of update that would include restoring windows. I think the only possible answer from here is a clean install using the USB.
But if there is anything on PC you need to save, try this
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 into command prompt and press enter
in notepad, click File>Open and this opens file explorer, use it to copy anything you want to save onto another USB or hdd
If you can get into command prompt, you might want to use it to wipe C drive as sometimes, if you try to use the USB to reinstall win 10 over a broken install, it can confuse windows. Easier to wipe C before installing
type
diskpart and press enter
type
list disk and press enter
this shows all drives available, DVD/USB and hdd, make note of hdd number
type
Select disk X - where X is the number of the hdd you want to wipe, change X to that number and press enter
once the drive you want to install on is chosen, type
Clean
Clean Install
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