If you don't remember your current root password and want to install new instance of MySQL and you have applied other ways like "-init-file.txt", but still failed.
There is another solution which worked for me. Uninstalling MySQL from control panel didn't remove all files, it left some references in the system.
To delete MySQL files completely, open the folder path C:Usersyour pc nameAppDataRoaming and delete the MySQL folder.
Then remove one more reference which is in C:ProgramDataMySQL, if not visible check your folder view options and uncheck "Don't show hidden files".
The last reference of MySQL exists in our system services:
Type "Services" in the search box of the taskbar. Find services related to MySQL and note them down. I have two in my case(MySQLRouter and MYSQL80).
Open the command prompt with administrator and type:
sc delete "ServiceName",
In my case:
sc delete MySQL80
sc delete MySQLRouter
Ensure all services related to MySQL are removed by using the above command. Restart your computer and install your MySQL instance with a new configuration.