How to trigger an uninstall from a program

Is there a way to uninstall a program, using my own program? My program is coded in VB6.

Here is my scenerio, my program, basically runs off a series of visual installs and when needed, sends keyboard input and uses sendmessage to buttons and tabs when needed.

Occasionally some of the programs we install, such as MSXML4, will mysteriously stop working and start spewing stupid errors. The only fix is to uninstall them, restart the computer, then reinstall them.

The question is, how do I start the uninstall procedure from my program?

Essentially I need to be able to detect if MSXML and one other inhouse app is installed, and then fire the uninstaller.

How do I fire the uninstaller?