While installing Microsof SQL Server 2012, I ran into the following error. "The SQL Server registry keys from a prior installation cannot be modified. To continue, see SQL Server Setup documentation about how to fix registry keys." How to fix Replace the D:\x64\FixSqlRegistryKey_x86.exe file with the original file from the ENU\SQLFULL_ENU.iso file downloading from Microsoft Download Center. This ISO file is 4.2GB. So you can click FixSqlRegistryKey_x86.exe to download this file only. After replacing that file, press Re-run to check. All rules are passed.
Practice until you can't make it wrong.