SQL installation guide
Configuration Manager required that you configure your SQL Server instance and Configuration Manager site database (if already present) to use the SQL_Latin1_General_CP1_CI_AS collation, unless you are using a Chinese operation system and require GB18030 support.
If you forgot to select the correct collation, instead of completely removing and re-installing, simple run the command below. More info: http://technet.microsoft.com/en-us/library/ms179254(v=SQL.100).aspx
Setup.exe /QUIET /ACTION=REBUILDDATABASE /SQLCOLLATION=SQL_Latin1_General_CP1_CI_AS /INSTANCENAME=MSSQLSERVER /SQLSYSADMINACCOUNTS=BUILTIN\Administrators
Fail to create SQL Server Certificate, ConfigMgr installation cannot be completed.