My multisim 8, doesn't work properly for unknown reasons. I wanted to remove/uninstall it but I can't, I keep getting the following error message: "The setup has detected that version 8.03.030 of Multisim 8 is already installed. This setup installs an earlier version of Multisim 8 (8.3.22). You will have to uninstall the previous version before installing this version."

I tried to install it again in order to get the "repair" button, but nothing is there... I really do not know what to do, and I have really basic knowledge about computers.

Please, I am desperate for help.