How do I upgrade old versions of app. installed using VS-Installer 1.1

[Bojangles]

I used Visual Studio 6 - Installer 1.1 to package my VB6 application. Customers have downloaded a trial version and then bought the licensed version. All has worked fine UNTIL now. I want to allow my customers to download and install a NEW VERSION.

I have read all I could find in HELP about Visual Studio 6 -Installer 1.1, and looked in forums, but cannot determine what I must do in order to properly distribute new (upgraded) versions while still using Visual Studio 6 - Installer 1.1.

I understand I could change my method of packaging and use something completely different such as Installshield, Wise, etc. However I prefer to stay with what I am using.

I assume I must uninstall the old .msi before installing the updated files, but, not being the brightest kid on the block, I can't figure out just how to do all this.

Please inform me what steps I should take to package and install my NEW version(s) on my customers' target machines, yet continue to use Visual Studio 6 - Installer 1.1.

Thanks much!