modem

If you've got the PCI slot and the correct driver, it should work. Make sure there is nothing else conflicting with the new modem.

Try booting into safe mode and looking at the hardware profile in Control Panel. There may be more than one modem installed that you won't see when booted in normal mode. Remove all modems and then try reinstalling the PCI one.

Also, make sure that if the modem has any switches or jumpers on it that they are configured correctly.

If you don't have the manual or drivers, I'd suggest getting a new one.

Watch during post that the computer sees the modem, check for IRQ conflicts.

In Windows, go to the device manager and check if there is a simple com controller or a pci communications device listed there . If it is listed there you need to selectit and click on properties, then update the driver.