this is very easy sir since the modem was intended for windows 7, therefore for windows 8 it needs the update for the drivers
these are some of the steps
1. install the modem
2. restart the system
3. go the device manager there you will find other devices (with a small question mark), in the submenu of other devices you will find usb modem (again with question marks)
4. just right click on the drivers and update, let the system automatically update the driver (you will need internet connection)
5. after update, just run the mmx device manager from the desktop.
then that will surely works
now enjoy the