SQL Server 2008 R2 not starting after moving model database
You probably moved the model database without issuing the required ALTER DATABASE statements. In the errorlog you will find the path where SQL Server expects to find the model database files (data and log) and you can move back the files to that location and start the service again. 

After the service has started, you can follow the instructions given here to move the model database to a different location.

Another possible cause could be the SQL Server service account is unable to access the path where the model database files are stored. Again, you can check it in the errorlog.