No not Safe Mode use Clean Boot.
If Clean Boot does not work, then attempt Safe Mode with Networking.
Does not always work and is a temporary fix if it works at all.
The once highly rated Avast is no longer recommended by most tech forums, it has become a monster in that it foists all sorts of unwanted junk on unsuspecting folk and they can be an absolute nightmare to get rid of, browser plug ins etc, there is also the matter of
Avast admits to ‘unacceptable’ sharing of user data: what you need to know
Windows 8, 8.1, 10 and 11 come with an improved Windows Defender, it offers the same real-time anti-virus/anti-malware protection as Microsoft Security Essentials. Windows Defender also shares the same malware signature definitions as Microsoft Security Essentials, and Forefront Endpoint Protection. Technically, Microsoft Security Essentials has not been renamed Windows Defender, or combined with it in Windows 8, 8.1, 10 and 11.
You can uninstall Avast in the Control Panel but should you have any problems see Avast clean removal info
here Please create a new system restore point first.
Once Avast has been correctly uninstalled, check to see if Windows Defender has auto enabled and allow it to update and carry out a full scan of your computer.
Another thing to attempt is creating a new user account on that system.
Not sure if we have attempted.
Then there is SFC.
Describes how to use the System File Checker tool to troubleshoot missing or corrupted system files in Windows 8.1, Windows 8, Windows 7 or Windows Vista.
support.microsoft.com