When Mitchel says it is stored in the database, it means it is stored in c:\Program Files\Microsoft SQL server\MSSQL10... and more according to your SQL version. That is of course if you use Microsoft SQL. From what you say, I think I may conclude you have set up dnn on your "localhost".
You don't have to be a programmer, but during the setup of dnn, you have to define your connection string to the database. You can do that in the setup wizzard, or you can define connection string by editing web.config.
Although your pages are stored in the path above (... and more), it has no use to go look there. You need a database client for that. The SQL server management studio (which you must have used to create the database and define access account in the first place) or the connection to the database in Visual Studio might give you access to the tables where the access is stored.
But again, this will be of little use for what you try to do, unless you really know what you are doing and as you stated, you don't.
If your site has been indexed by google, you might still find some cached pages there. That is how I once got through a crisis like yours.