Avast Clear is a utility for deleting avast applications, when the standard way from the Windows control panel (for example, you forgot your password, which protected your antivirus settings) cannot be deleted.
How to uninstall software with this tool:
Log in to Windows in safe mode.
Run the utility.
If you installed avast! in a folder not by default - select this folder (Attention! All files from this folder will be deleted).