Imposssible to expand a database in SQL Server Management Studio
Open a new query window and run SELECT * FROM sys.databases.  See if the database in question is listed in the results.

If it is, see if you can access it by running USE MyDatabase.  If that works, see if you can pull up a list of tables by running SELECT * FROM sys.tables.

You may want to run DBCC CHECKDB MyDatabase and see if any problems are detected.