In my installer, I am having two issues when running against a machine with a previously installed version.
First, both the old and new version show in control panel. The upgrade code for the old version and hte new version match. I have regenerated the product code.
Second (and likely related to the first) --
I have a custom UI dialog that should only display if upgrading a previous installation. I have a "show only if" condition of (UPGRADINGPRODUCTCODE). The dialog doesn't show no matter what.
I do have a third issue that isnt' applicable to this install, but will be for future installs. I'll need to know the version being upgraded.