Hi,
simply put, when you publish something in the portal (or use launchpad links on the desktop/start menu). You should always have matching the scheduled task on the server. The process behind the portal checks on the server for the active actual content (tasks) it needs to display. Tasks (links) that you delete on the server will disappear from the portal. This is how you maintain the contents of the portal.
On the other hand, if you use a scheduled task to do software distribution, and the user uses the icon created by that distribution in the start menu or desktop, than you can delete the scheduled task after all are succesful. This will not automatically uninstall the software! At most it will again remove the link to the installation from the portal, if you used the portal in the first place.
Frank