sencar

I have a newly re-installed XP + SP2 and a cable modem. I can browse the web and use mail via Outlook Express but no-one seems to recognise that I have a connection. These include: Windows Update (tells me I'm not connected), AVG Antivirus update (ditto) and my share price download prog (operates on ports 7000 and 80 but won't download). I have no hardware firewall and only Windows firewall in software (I turned AVG f'wall off) Any suggestions please? Sencar