=====List instances of SQL Server installed=====

Call “command window”. You can do it by:
Clicking of “Windows” button + R and in the prompt which will appear writing “cmd”

or

Clicking on the search icon and searching for “cmd”

In the command window type the following command and press “Enter”

sc query | find /I “SQL Server (”

If command does not return any results then there are no SQL Server instances on this computer