wppar

In the event of lost password not working then the next thing to try is using phpMyAdmin to manually reset the password in your WordPress database. This should be found in your webhost provided database utilities.

I have attached a link below that explains what is involved.
https://www.wpbeginner.com/beginners-guide/how-to-reset-a-wordpress-password-from-phpmyadmin/

Apologies for link not being attached. Hard coded below.
https://codex.www.ads-software.com/Moving_WordPress#Moving_Directories_On_Your_Existing_Server

Link for above post

Hi ruauu2,
The below link explains the process for changing the url of an existing WordPress installation, ie. moving directories.

Hi Nicola,
Sometimes plugin conflicts can cause problems with logging into your admin area so I would start by disabling the plugins you updated along with WP4.0.
To disable plugin files in this instance you will need to use the File Manager provided by your webhosting company or an ftp program such as Filezilla and simply rename the appropriate plugins in the plugin folder at /wp-content/plugins from eg. myplugin1 to say myplugin1-deactivated.
This will at least remove the plugins as the cause of your problem.
If you are still unable to login then go to your WordPress login page and click on lost password to renew your password through the automatic emailer.
Assuming you are now logged back in to the admin dashboard you can then reactivate your plugins one by one to see which one is causing the problem.
Before updating plugins if you take a copy of the plugin and rename it in the plugin folder you will then be able to revert back to the previous version if the latest version doesn’t work.