You should run the repair from the original installation media, using the following command line:
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 Files\Microsoft SQL Server\100\Setup Bootstrap
- For SQL Server 2012:
C:\Program Files\Microsoft SQL Server\110\Setup Bootstrap
https://support.microsoft.com/en-us/kb/969052