When you install a Magix program, there is a screen with three subjects. The first is to modify the defaults, the second is a checkbox accepting some other programs, including the Update Notifier which is what puts the adverts at the lower right of your computer when you boot it, and the third is Terms and Conditions. If you did not uncheck the box, then you installed the Update Notifier.
You can go into this in the hidden apps tray at the bottom of the screen and select only those products for which you want to receive adverts or none, or you can uninstall the app as per the thread indicated by Stephen.