Hello!
My name is David N., and I am a Windows fan who assists others with issues in this community. I will be happy to assist you with your issue.
The password protection for uninstalling Avast is part of the Avast product rather than a Microsoft product. This forum is for Microsoft products, and so we can offer limited assistance.
However, I have found two webpages that explain methods to do this:
https://www.avast.com/uninstall-utility#pc
Follow the instructions to "Uninstall Avast using Command Prompt". Start with the tip at the bottom to disable the password protection.
https://support.avast.com/en-ww/article/10/#art...
This is the webpage for their Avast uninstaller tool. The instructions here should allow you to uninstall the product by booting into Safe Mode and using their tool to get around the password protection.
I hope this helps! Please let me know if this resolves your issue or if you require additional assistance.
Regards,
David N.