title: Visual Studio 2010 update registry in setup application
body: <p>I've recently created an application for my brother to use, it has several entries stored in the registry that it uses. I created a Setup Application in VS2010 so he can install the application to his PC with ease and set the entries to some default values for him, which he has changed. e.g.</p>
  
  <p>I have a entry called "SummaryFolder" and the value of "Successfully Installed" - so when it was installed it would have the default value. He will have changed this by now to an actual folder on his PC.</p>
  
  <p>Now I've just made a change to the program and added a couple more registry entries, modified the setup application and added in the new entries for installing. I've changed the build number of the setup app, so when he installs the app, it actually UPDATES his existing version. The problem I'm having is that the existing registry entries he has from the initial installation has been overwritten with the default "Successfully Installed" values, hence removing the folder he set.</p>
  
  <p>So my question is: How can I specify for the setup program to only add the registry entries if they DON'T already exist ??? I want to have the installer to be as simple as possible for him.</p>
  
  <p>Many thanks for any help.</p>