Built an MSI on the Web Setup Project template in Visual Studio 2005 on my Vista dev machine and tried to install to a Vista Home Premium machine. The MSI quickly stops and says "Installation Incomplete", without any useful feedback.
I created a log file, the fatal error code was 1603 but that didn't lead to much help.
Tried Windows Installer Cleanup Tool, no help. Tried upgrading to Installer 4.5, no help. Finally I remembered a post that mentioned IIS 6 compatibility being required for some MSI packages (http://forums.karamasoft.com/ShowPost.aspx?PostID=6495). I had ignored it since I was building on Vista with IIS7, and installing to Vista with IIS7, but of course....
Went to Control Panel, Programs & Features, Add/Remove Windows Component - turned on all the IIS6 compatibility options and retried the MSI. Installs clean now.
Lesson? I believe since Visual Studio 2005 was released at the time of IIS6 it still relies on the old API, so keep this in mind when installing web setup projects to Vista boxes.