Everyone on the planet reviews the usual firewalls, ZA, BID, TPF, NPF but you might want to look at some of the more esoteric among the candidates. I know where you can get them all in one place. You can e-mail me for the info. Admins only.
I had a Conexant HFC modem and had the same problem with XP. I found a generic Conexant HFC driver and installed it and it ran fine. It just did not have the voice capability. I have the driver although I finally switched to an ESS with plenty of XP support. If you want the driver I can e-mail it to you. roban@optonline.net