Off Topic: Install\Uninstall Problem concerning a MFC Application

I know I am off topic here but I believe someone here will have
experience with a problem I am facing and its a MFC application I am
trying to install.

If there is another newsgroup someone knows of I would considering
trying that may help as well.

The Problem ....

I have a very simple application that is going to be released in its
second version. The first version was installed using a old version of
Wise installer 6.0.

The new release version of my app is on the latest version of Wise

I need to be able to blow away the first version off a users machine
and install the new version. The reason for automating this is our
users are not savvy users of Windows.

The problem I am running into is the application is always running, as
its a system tray application, and its on all Windows OSs from Win 98
to Win Vista. I have created a terminate app executable (seperate
process called from the new install) that will terminate the
application but how do I uninstall the old version. I need the new
install to wipe out the old registry settings,a Desktop icon, a File
Directory, and few menu items. This application consists of less then
10 files and a dozen registry entries.

Now the file directories and the registry settings should not be a big
issue but how do I remove the Desktop, Menu items on all Operating
Systems, if I remember correctly aren't they in different locations?
If so, does anyone know these locations?

I know the location of the original installed files (the system tray
executable location) but not how to remove the incidentals such as the
menu items and the desktop icon.

Is there a registry setting somewhere for each Operating System Menu
\Desktop item?

As I have little experience programming for Vista will there be any
security issues I must tackle before deleting files/registry settings
on Vista.

I have tried the preferred method of calling Wise's "UNWISE /S
install.log" to uninstall the old version, which works, but in Windows
Vista all the allows/cancels and the Unwise executable allow\cancel
message would even make me question continuing the new install.

Any Ideas?