If you are an Administrator or Designer, and you accidentally remove the System Region within your Login Page's Page Style, liveSite will not be able to display the username and password login fields. This means that no one, including you, can login to liveSite using the login page at this point. If this has happened to you then you may follow the instructions below. The instructions below are for v8+. If you are using a version before v8, then you can ignore steps 1-4 and you don't have to add "&token=token" to the URL mentioned below.
NOTE: You can always get to the default login page by adding the directory off your web root where liveSite is installed (e.g. http://www.yourdomain.com/livesite, or http://www.yourdomain.com/login, etc.).