You need to take some steps in order to fix this issue.
First, uninstall the MTN online software and unplug the modem then uninstall the software and delete the folders that contain MTN (Online & F@stlink). Install the MTN Online software, make sure the modem is not plugged in. Restart the computer, plug the modem and let the software install and then disable any Windows Updates because this may break compatibility due to security updates.