To make the modem work in Windows, you will need to install the drivers manually. Go to Device Manager, right click the modem device with the yellow exclamation mark and select Update Driver. Point the installation window to the folder where the associated software installed (usually Program Files) and confirm the installation once the drivers are found. It will warn against possible conflict, but that's Windows attempting to block the installation because it's not signed. Once completed, reboot the computer and you'll have a USB modem installed in an unsupported operating system.