My application can either run using an existing SQL Server instance (local or on a server) or install SQL Express locally.

I created a c# program that will check if SQL Server is installed locally, and if not it will ask the user if SQL Express should be installed. I created a new bootstrapper package for SQL Express SP3, use an external check to launch this program and use the return code to check the users' selection. However, if the user presses "Yes" the bootstrapper will still still show "the following components will be installed on this machine".

Is there a way to disable the confirmation window?

If not, is there another way to optionally install a pre-requisite? It would be really convenient if there was a merge module for SQL Express, but alas.