SQL Server 2008 Express Edition || Windows & || Unable to create DB.

I have SQL Server 2008 Express edition installed on my windows 7 Machine and I am unable create a DB on this. I receive follwoing error from management studio. TITLE: Microsoft SQL Server Management Studio ------------------------------ Create failed for Database 'MyDB'. (Microsoft.SqlServer.Smo) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.50.2500.0+((KJ_PCU_Main).110617-0026+)&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Create+Database&LinkId=20476 ------------------------------ ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo) ------------------------------ CREATE DATABASE permission denied in database 'master'. (Microsoft SQL Server, Error: 262) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=10.00.4000&EvtSrc=MSSQLServer&EvtID=262&Li ...