You can select from one of the following links to download the appropriate driver.
http://broadband.custhelp.com/app/answers/detail/a_id/21177
http://broadband.custhelp.com/app/answers/detail/a_id/21848
http://www.motorola.com/Support/US-EN/Consumer-Support/Cable-Modems-and-Gateways
After you have downloaded the driver, the next step is to install the file you have downloaded. This installation is similar to most software installations. After the installation has been completed, connect the USB cable to your surfboard modem and the computer should do the rest automatically.