The MSSQLServer service terminated unexpectedly. Check the SQL Server error log and Windows System and Application event logs for possible causes.

Solution: 

Oops! You might be running a very old build of SQL Server. Immediately check for new release of Service Packs, I would recommend installing recent service pack and then the latest cumulative update package.


If the Service pack installation didn't solve your Issue

For additional help, Open a case with Microsoft immediately.