In some situations you might want to perform an in-place upgrade from say SQL 2008 R2 to SQL 2014, rather than a fresh installation.
First thing to do is to run the Install upgrade advisor, this can be sound by running the setup.exe in the SQL 2014 installation disk, selecting Install Upgrade Advisor from the planning menu.
You might get an error as shown below. To solve this, run/install components for SQL 2014 which can be found by clicking here.
After a restart, you should be able to run the install upgrade advisor, which will be accessible from Start/PRograms/SQL 2014/SQL Server 2014 Upgrade Advisor