problems with Joomla

We've just installed a joomla website template and have created a database for it on our server. However, when we try to log into the administrators console we keep getting a message saying incorrect username, password, or access level. The username and password are the same as when we first installed the site. Is there something obvious we should be doing to allow us to gain administrators access to the site? Or is there some way we can edit a file that will allow us access? Incidentally, we've managed to login to the site as a normal user i.e, by registering on the front page.