This is the first time I used SQL Server 2008 Express. A most interesting experience. First off there are several types, database only, management tools only, both and Advanced Services that comes with reporting services. I installed the database only and tried to reinstall it with Advanced Services and got no where. In the end I removed it and installed the Advanced Services package.
The SQL Server 2008 Express by default on startup will dynamically bind to a random port. If connecting remotely, you need to change this to a static port. You need to configure the port number the database engine is going to listen and enable the interface. Surface Area Configuration Tool? This has been discontinued.
Lastly connecting to Server Express using Management Studio requires you to specify the instance name. For a full SQL Server, you specify the <server name> in the management studio. For SQL Server Express, you have to specify <servername\instance name>.
Types of SQL Express, Enabling remote access Surface Area Config