Example of An Online Drupal Site
This is the usual situation where you can easily log into your administrator account and modify the settings to your account.
Example of An Off-line Drupal Site
If you are reading this tutorial, you are likely faced with this situation...no login. Do not panic! There is a simple solution!
www.mysitesurl.com/?q=user
Just type, ?q=user after your site's root url, e.g. www.mysitesurl.com/?q=user, and this will get you to the hidden login page.
Access Site Maintenance Section
Go to the Site Maintenance Section by clicking on Operating in off-line mode
Set to Online
Pretty simple here. Just set it to Online and save.
Mission Accomplished
You can check your site now and see that it is back online!