Pci modem. my computer is equipped with windows xp sp2 operating ystem.in device manager it shows

Question

my computer is equipped with windows xp sp2 operating ystem.in device manager it shows a pci modem with a yellow question mark sign which means its driver has not been installed yet.i have no driver software for this.i found in my cpu cabinet that there is a small modem atached in my pci holder.now what should i do to geting proper driver software for my modem