Oh good lord this brings back memories of a VBS script I cobbled together years ago that would bring up an HTML interface that would let you enter a computer name, and if it was on the network it would scan the remote registry for things in the Uninstall key, strip out KB's, and give you a dropdown list of things to uninstall. Hundreds if not thousands of lines of script that I'll never use again. Anyway, enough reminiscing.
You should be able to use the Call operator "&" to run the string in the UninstallString property like such:
& $App.UninstallString
Now, having said that you'll want to take something into consideration. If it is something executed with MSIEXEC.EXE there's a really good chance that they have it set to MSIEXEC.EXE /I {<some GUID>}
and you will probably want to replace the /I
with /X
and append /NB-!
to the end of the string (if I remember my switch right that will give a minimal progress bar display and suppress any "Uninstall Complete" windows that may pop up).