SQL express saga and a database size limit.

This is what happened. I had SQL 2012 Express versions installed on my machine. All worked well until I had to restore a sitecore master db that was PRETTY BIG. I didn't realize that SQL Express has size limits on databases. So I got this error:

I attempted to 'upgrade' SQL Server from Express to full by clicking on Maintenance in the Setup wizard but had not luck even though the install went through. I had to uninstall SQL Server all together and install again, but this time the full version.

Then of course I could no longer load the sitecore site that had connection string pointing to SQL Express, since Express was no more. I decided to attach a master....mdf file in the Databases folder in the root to the server but got this:

A colleague of mine said that if a db was created under Express you cannot use it under full SQL Server. Booo...