can't login

I installed through HG QuickInstall and copied the User name and password as suggested. If I type in my domain name it will show the Hello World page. However, I cannot login to wp-admin and am advised that my login is an invalid username. If I try to set a new password it won’t accept either my user name or my email address. I am informed that my email is not registered with wordpress.
If you wish to view my website details are http://www.dfagencies.com and my email address is donf1939@gmail.com.