The SQL Server (MSSQLSERVER) service terminated with the following service-specific error:
%%17051
The SQL Server (MSSQLSERVER) service terminated with the following service-specific error:%%17051. This was the error while I was trying to start the Microsoft SQL Server 2008 R2 standard edition on my Microsoft SharePoint 2013 Server. After a little struggle and looking at the event view of the system I found out that the trial period of Microsoft SQL server 2008 R2 Standard edition has been expired.
if you like to keep the Microsoft SharePoint 2013 Server up and running then you need to repair the Microsoft SQL Server 2008 R2 Server and provide a valid key to activate (this was in my case because I was using this Microsoft SQL Server 2008 R2 for SharePoint). You can follow the instructions given in the link to enter the key for activation. You can upgrade the version of Microsoft SQL Server 2008 R2 to Microsoft SQL Server 2012 R2 with a valid key. Follow the under given pictures to enter the Key. 
After completing the process successfully, please start the Microsoft SQL Server 2008 R2 service from services panel and you are good to go.
