You'll probably need to be at least an advanced beginner with self-installed WordPress installations to do this.

The situation:

You can't get into a WordPress installation, you don't have a working e-mail address so you can't reset your password.

However, you can getinto the mySQL database.

The Solution:

1) Log into your cPanel 

2) Go to PHPMyAdmin

3) Open the database which connects to your website

4) Find the table wp_users

5) Find any user identity there and change the e-mail address in the e-mail column to an e-mail address you can access  (Please excuse my sloppy pink arrow in the image below) Make a point to remember what is in the user_login column in that same row.  Will come in handy later

6) Go back to the admin panel www.yourwebsiteaddress.com/wp-admin

7) Now choose lost password and enter the e-mail address you used in step 5

8)Go to your e-mail to reset the password

9) Now login using the username you "remebered from step 5 and the new password you recently reset.