Hi, I'm Benedict, an Independent Advisor. I'm here to help you.
Running Microsoft Defender Offline Scan should shut down your PC in order to start scanning. And that issue of yours might be caused by that malware you have mentioned above and it might have already corrupted some of your system files that made your system's security app malfunctioning. Try to scan your PC with these methods:
- Run a scan with the free version of MalwareBytes, you can download it here: https://www.malwarebytes.com/mwb-download/
Once installed, open it and go to Settings > Security tab > enable all options under "Scan options." After that, close the Settings and click on Scan button to start scanning. Quarantine the detected threats, if any, then restart your computer and run a scan again until no more detected threats.
- Run a quick scan (or full scan if the quick scan didn't help) of Microsoft Safety Scanner that can be downloaded here:
https://docs.microsoft.com/windows/security/thr...
- Use the Windows Malicious Software Removal Tool:
For 32-bit x86-based systems: https://www.microsoft.com/download/details.aspx...
For 64-bit x64-based systems: https://www.microsoft.com/download/details.aspx...
If that doesn't help, try doing a repair install of Windows 10. This will fix and replace all missing and corrupted system files by reinstalling Windows 10 with the option of keeping your files and all installed apps including third-party apps. Go to the link below and follow the steps provided by Shawn Brink, a trusted Windows Insider MVP.
Repair Install Windows 10 with an In-place Upgrade: https://www.tenforums.com/tutorials/16397-repai...
Please see if that helps.
Regards,
Benedict P.
Standard Disclaimer: There are non-Microsoft websites mentioned above. These pages appear to be providing accurate, safe information. Watch out for ads on those sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on those sites before you decide to download and install it.