If the modem is on COM5, this suggests to me that your computer thinks it has other modems installed. Normally a pci modem takes the next available COM port. As a desktop computer generally has COM1 and COM2 as connectors to the outside world, the modem will generally be COM3. Take the modem out of the computer, then in Device Manager remove any references to a modem or enumerator. Make sure that there are no modems listed in the Control Panel, and no drivers in Add/Remove programs. Next install the drivers strictly as instructed, this will sometimes be done by installing the drivers before the card, and sometimes by fitting the card and letting the New Hardware wizard find the driver.