You should run the repair from the original installation media, using the following command line:
Repair the common shared components and features first, and then repeat the command to repair the instances installed. During the repair process, the setup dialog box disappears. As long as the progress window does not show an error, the repair process is proceeding as expected.
Note The following error messages can be found as text messages in the event log or in the Setup logs that are located in one of the following folders, and they indicate that you should repair your affected instance being proceeding further:
setup.exe /ACTION=REPAIR /INDICATEPROGRESS=TRUE
Repair the common shared components and features first, and then repeat the command to repair the instances installed. During the repair process, the setup dialog box disappears. As long as the progress window does not show an error, the repair process is proceeding as expected.
Note The following error messages can be found as text messages in the event log or in the Setup logs that are located in one of the following folders, and they indicate that you should repair your affected instance being proceeding further:
- For SQL Server 2008 and for SQL Server 2008 R2:
C:Program FilesMicrosoft SQL Server100Setup Bootstrap
- For SQL Server 2012:
C:Program FilesMicrosoft SQL Server110Setup Bootstrap
参见：
https://msdn.microsoft.com/en-us/library/cc646006%28v=SQL.105%29.aspx
https://support.microsoft.com/en-us/kb/969052