title: Installing SP2 for SQL Server 2008 R2 Express
body: <p>I need to upgrade SQL Server 2008 R2 Express from SP1 to SP2.  Select @@Version reveals 10.50.2500.0</p>
  
  <p>I've downloaded what I think is the correct package but when I try to install I'm prompted to install a new instance or upgrade an existing instance.  Choosing the 2nd option eventually gets me to the point of choosing Mixed Mode or Windows Authentication.  I know what that is, but, why is it asking me this?  I do not want to change <em>ANYTHING</em> about my environment other than installing the Service Pack, including authentication mode, or the password of the SA account, etc.</p>
  
  <p>Am I doing something wrong?</p>