My new pc came with a hamr modem. I am not satisfied with the hamr so I purchased a new us robotics performance pro 56 k modem and when installed the pc will not shut down. Prior to installation of the new usr modem I removed drivers for the hamr modem and I also went into bios setup and disabled "on board modem".

I have also noticed that in system tools that it specifies a problem device:
acpi irq holder for pci steering, acpi/*pnp0c0f/\00000003.

I have spent many hours trying to get the usr modem working but have now had to re-installed the hamr modem.

Any ideas?