Hi
Greetings! I am Vijay, an Independent Advisor. I am here to work with you on this problem.
A. You should restore / reset your computer using Media Creation Tool. You will have to cut Media creation tool on another computer if you can't do this on your existing computer.
Refer to the section"Use installation media to restore or reset your PC "
Recovery options in Windows 10 - https://support.microsoft.com/en-in/help/12415/...
Note - You will get the option to keep your files during reset. But it will remove third party apps including Microsoft Office which will need to be reinstalled. Default Windows 10 apps will be automatically installed. But non-defaults Windows 10 apps will need to be reinstalled.
B. If A doesn't work - I would recommend that you should consider a clean install of your existing Windows 10. You can use below guide by Greg Carmack, MVP for this purpose. This is the best method to perform a clean install of Windows 10. (If you want to rescue your files, there is a section Rescue Files when Windows Won't Start)
https://answers.microsoft.com/en-us/windows/for...
If you want a very lightweight guide - Start fresh with a clean installation of Windows 10
https://www.microsoft.com/en-us/software-downlo...
Do let me know if you require any further help on this. Will be glad to help you.