I can't connect with database under root. (no replies)

Windows operation system.
- Installed MySQL
- I have Removed MySQL
- Have installed MySQL anew in other folder
After pressing "Execute" in the Configuration Wizard in the
window Processing Configuration the Message "Could not start the service MySQL" appears and security settings don't apply.
I have corrected a configuration (my.ini) file. The service started.
But I can't connect with a database under root.
Explain me please, why the message appears:
"Error 1045 (28000): : Access denied for user 'root'@'localhost' (using password: YES)"