How about this?
http://www.microsoft.com/windows/ie/downloads/recommended/128bit/default.mspx
To be honest, for your own good I would contact HP and get a new install disk. They may be free if the machine is not that old. You will need it. If not now, sometime. Do you have the XP firewall on? Personally, I do not like Norton and have a hunch that is the root cause.
I have an older version of Norton Firewall that has served me well, yours sounds newer, so this may not be of any help.