Can windows start? If you are getting into Windows now try the following.
Try running in administrator command prompt. Copy and paste the commands from here to command prompt. 2 commands below.
If you get errors reboot and run again until no more errors are found. I do hope this works for you. Both commands take a while to run.
Open the command prompt by typing command prompt in windows search bar It will show up on top, right click and choose run as administrator.
sfc /scannow (there is a space between the sfc and/)
dism /online /cleanup-image /restorehealth ( same space between all words and /)
If these commands don't work and you can work in the desktop try to download the ISO file of windows 10 from the website to the downloads folder on your hard drive. . Save it to your downloads folder. Go to your downloads folder . Mount it by right clicking
. Run setup..exe. You may need to show hidden files. Just run the setup right over the existing one.
Windows 10 has been a disaster for many users. I do hope something will help. You mmay have to resort to a clean install. If you are getting into Windows back up anything important to you to external drive or usb flash. Do you have any other antivirus installed
other than Defender? Uninstall other antivirus or malware software as they interfere with Windows. You also may need to update drivers. Sorry You now get a new error.
Also try this website for more info
https://www.howto-connect.com/sihost-exe-unknown-hard-error-windows-10/
Do not download their software. Just do the steps.