Symptoms

You get a message saying that your modem isn’t responding. You must restart your computer every time to get your modem to respond.

Cause

This problem occurs because the Modem.sys modem driver enters an infinite loop. The modem driver enters an infinite loop when a program tries to access the device when no phone call is initiated and no voice modem functionality is in use.

Resolution

To resolve this problem, obtain the latest service pack for Microsoft Windows XP.