Right-click on My Computer from the Desktop, then choose the Device Manager tab. Click the + next to Modems to expand the selection. Select the MT5634ZBA-USB and click the properties buttom below. Select the Driver tab and click the update driver button below. Select the Specify the location of the driver (Advanced) and click Next. Check the Specify a location option and Browse the the install CD/Disk and use the Windows 9x/ME drivers. This will use the ATLAS drivers, which work properly.