To install just unzip it to a named folder eg. conexant driver (using a zip utility such as winzip or powerarchiver) then go to the control panel then system then device manager search for HSFMODEM which will be the pci enumerator for the modem, click properties update driver click specify location input the name of the folder that you extracted it to eg. conexant driver and then wait for windows to work its magic.
P.S. if you dont understand a word you just read theres a little diagram which might be of some help to you.
[Unzip to Folder (conexant driver)--->go to Control Panel--->system--->device manager
update driver--->specify location
--->folder (conexant driver)]