Sometimes another program, such as a fax or voice mail program, may be accessing the same comport that the modem uses.Here's how to check. Hold down "ctrl-alt-delete" at the same time for a second and a screen like below should come up. If a program you suspect may be accessing the same com port as the modem is running, disable it by highlighting it, then click "End Task". If no programs are running, click "Cancel" and no harm done. (Don't press "ctrl-alt-delete" twice or computer will restart.)
Sometimes another screen will appear like the one below. Not always, but if it does simply click on "End Task again".
Tell member that they may have to do this everytime if the program starts everytime they turn on the computer.