Did you install any early version of SQL Server on the computer? If you had install SQL Server 2000 before, this may be related to Microsoft SQL Server 2000 Desktop Engine(MSDE) instance on the computer. It seems that the SQL Server 2008 R2 does
not have problem with the MSDE stuff as the way the SQL Server 2012 installer does. If the issue is caused by SQL Server 2000, you can refer to the article below to remove the MSDE. http://support.microsoft.com/kb/320873