When attempting to install Microsoft SQL Server 2008 under Windows Server 2012, you are presented with a warning dialog stating “this program has compatibility issues.” You are then given the option to choose to “Get help online” or “Run the program without getting help.”
Selecting Run the program without getting help will allow you to install SQL Server 2008. After this is complete, apply Service Pack 1 for SQL Server 2008 from Windows Update before proceeding with configuring the SQL instance. This will allow you to use this SQL instance in your Windows Server 2012 deployment.

Program Compatibility Issues Error during SQL Server 2008 Installation