Revision to install - Citrix client package

I am using WinInstall LE.  What do I need to change so that it ignores previous feature states? 

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I have created a custom msi for installing citrix client package on my network.  The original MSI had three options; web client, program neighborhood, and the program neighborhood agent. 

About a month ago, I created a custom install (Lets call it 8.0.1) that only installed the program neighborhood.  It marked the other options as unavailible.  This is a silent install.  I had to go around an put new video cards in the 40 machines it needed to be installed on, so I just installed it locally at the same time. 

Now after studing our needs, we should be using the PNagent instead.  So I went back and created a custom MSI (lets call it 8.0.2) that installed the program neighborhood, and the program neighborhood agent as well as all the setup information for pnagent.  The web version is still left as unavailible.  I changed the version number of the MSI using WinInstall so that it would install over the original 8.0 install. 

The problem that I am having is that if I install the package on a new machine, all the correct componets are installed.  If I install the package on a machine with 8.0.1 installed on it, it goes through the actions of installing the PNagent, but it does not install.  I know that it went through the action of the install because it only prompts for a reboot when installing the PNagent.  If I perform an uninstall, then reinstall 8.0.2, it works just fine.  Is their a way to force the uninstall of an application before the new package is installed without a user interface? 

Any suggestions?  I have just recently started working with MSIs and have been using WinInstall LE for everything.