db connection error in sql server 2008 and visual studio 2010

Question

i am new to visual studio 2010 and sql server 2008... but i am good with db connection in visual studio 2008 and sql server 2005.... now the worst part is after installing vs2010 i start to create database as i followed in vs2008
1)db explorer-->data connections right click and selected add connection
2)in next window i selected data source as Microsoft SQL Server Database File (SqlClient)
3)in database name i gave some name like db after tat i pressed k button... it asked for conformation message as database file does not exist would u like to create i selected yes but it shows error as
failed to generate a user instance of sql server due to failure in starting the process for the user instance. the connection will be closed

could anyone solve my prob its very urgent......