Visual Studio 2010 SQL Express 2008 SA Account
VS2010 configures SQL Express for Windows Authentication and disables the SA account
You must install SQL management studio 2008 R2 in order to change the SA password
SQL management studio must be Run As Administrator or you can’t do anything (right-click the icon and choose Run As Administrator).
then you must turn on mixed mode authentication
then you can enable the SA account and set the password