In order to fix the issue, right-click on the Computer icon, select Manage and open Device Manager. Expand the Universal Serial Bus controllers and Network Adapters lists and locate the Modem. Once you find it, right-click on the driver, press Uninstall and follow the provided instructions. After that, reboot your PC, connect the USB modem and press Scan for hardware changes icon from Device Manager. Windows will automatically find and install the drivers.