HP Compaq Presario,Presario 2100 Reference Manual page 81

Open the hardware Device Manager. Select Start > Control Panel > Performance
and Maintenance > System. If the modem is disabled, try to enable it. If it has a
conflict, try disabling another device.
If you're running fax software using fax Class 2, try using Class 1.
If the modem dials but you can't hear it
If your model has an audio mute light, make sure it is turned off. If it's on, press
the audio mute button.
Check the speaker volume setting.
In Control Panel, open Phone and Modem Options, then select the modem and
select Properties. Check the volume setting on the General tab.
If the modem connects, but transferred data is bad
In Control Panel, open Phone and Modem Options. Make sure the parity, speed,
word length, and stop bits match on sending and receiving modems.
Try a different phone line or dial a different server number.
If the modem causes an ERROR message
A string of AT commands may contain an incorrect command. If you entered
commands as extra settings for the modem in Control Panel or in your
communications software, check the commands.
If the modem doesn't fax
If you're using fax Class 2 in the fax software, try using Class 1.
Close any other communications programs.
If you're faxing by printing from an application, make sure you've selected the
fax printer.
Try turning off power management features temporarily.
If excessive line current is detected
Make sure you're using an analog telephone line (2, 3, or 4 wires). You must not use
a digital line. In a hotel, ask for a data line.
If the modem clicks repeatedly but doesn't connect
Make sure you're using an analog telephone line (2, 3, or 4 wires). You must not
use a digital line. In a hotel, ask for a data line.
Check all cables and connections.
Troubleshooting and Maintenance
Troubleshooting Your Notebook
Reference Guide 75