Have a look at the services running on the box. If Notification Services is not there then it is not installed.
Be aware that Notification Services is deprecated in SQL Server 2008. If you are not already using it then you should not start to use it.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
When I give food to the poor they call me a saint. When I ask why they are poor they call me a communist - Archbishop Hélder Câmara