No apologies needed. There are lots of AOL users here.
AOL 9.0 does not use its own dialer (unlike 8.0). It uses the Windows modem properties. I believe turning off the "modem speaker" disables all sound since laptop modems do not have their own speaker. So have her check the modem properties in control panel.
The other place to tweak this is in the AOL System Information utility. There's a modem tab in there where some settings can be adjusted.