I am unable to attach a database my SQLExpress Server

I'm using SQL Server 2005 Express Edition with Advanced Services on a Windows 7 platform.
When I try to attach a database using MSE I get the following error:
TITLE: Microsoft SQL Server Management Studio Express ------------------------------ Failed to retrieve data for this request. (Microsoft.SqlServer.Express.SmoEnum) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&LinkId=20476 ------------------------------ ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.Express.ConnectionInfo) ------------------------------ CREATE FILE encountered operating system error 5(Access is denied.) while attempting to open or create the physical file 'C:\Program Files\Microsoft SQL Server\MSSQL.2\MSSQL\Data\2010-2011.mdf'. (Microsoft SQL Server, Error: 5123) For help, click: ...