SQL Server 2008 R2 can't connect to local database in Management Studio

Question

I am using SQL Server 2008 R2 Express.

I first installed SQL Server 2008 R2 Express Management Studio and then I installed SQL Server 2008 R2 Express. I have the ins

Answer 1

Lots of the above helped for me, plus the accepted answer, but since I was on an EC2 instance, I had no idea what my instance name was. Finally, I opened SQLServer Configuration Manager and in the Name column, use whatever is there as your connection server, so in my case, .\EC2SQLEXPRESS and worked great!