Franc Zabkar wrote:

98se and puppy Linux live cd does recognize my ISA modem
(cl-md56xx cirrus logic)

The xx is important. Some 56xx modems were controllerless,
others had a hardware controller.

I'm fairly certain that _no_ ISA-based modems were controllerless.

The best modems were in fact ISA-based, because they always had on-board
processors and did all the communication work themselves, as opposed to
controller-less modems (which as a rule were are all PCI-based modems).

The OP is advised to remove the PCI modem and get XP to recognize the
ISA modem. His anemic system doesn't need extra load of dealing with a
controller-less modem.