modem conflict in XP

[Mike]

I have a Toshiba laptop w/XP Professional SP1. When I use
the internal modem, the computer slows down (with no
apparent activity) and locks up.

I've updated the modem driver from Toshiba, updated BIOS,
keep current from windowsupdate.microsoft.com. I've
looked at COM settings to make sure the modem is on a
different serial port from the mouse, I've changed IRQ
control from "OS" in the BIOS to see if that changes.
Device Settings indicate that the modem is working
properly with no conflicts.

I've unistalled/reinstalled the modem, updated/rollback
drivers, uninstalled/reinstalled the dialup software, and
even tried a different dialup program.

I've checked the modem using diagnostics and a
hyperterminal to the port and it's OK.

I just ran msinfo32.exe and found that the modem is
sharing IRQ11 with the USB ports, sound cards, and other
devices.

The behavior is just like a device or IRQ conflict, and
other than dialup, the laptop works fine.

I'd like to be able to work with IRQ and COM port settings
and get past the HAL in this one. What should do?

Thanks, Mike