Dead End

Firstly, I have read and followed in full the How to: Spyware, Trojan And Virus Removal on this website.
Second, I use Firefox as my primary web browser although the problem I will describe happens in IE as well.
So the problem is that I am unable to bring up web content on numerous web sites (http://www.seagate.com) is a good example. The name resolves to the correct address when you ping it and I can get to it from other computers in my network (all going through the same firewall). There are no outgoing rules on the firewall preventing access. All I get is "The document contains no data" in Firefox and in IE it takes me to the msn search page (default when page is not found).
I have run all the spyware, and virus programs (actually the How To was a very good procedure). Everything is clean with the exception of when I run Spybot - Search and Destory I get the same 5 DSO Exploits. Each of the 5 are in HKEY_USERS and correspond to the 4 profiles on the machine as well as the .default profile. They all say HKEY_USERS\[profile]\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\0\1004!=W=3. Now I don't know why but every now and then the 1004 key changes to a string value instead of a dword value. So I delete it and recreate it as a dword value but Spybot still reports the same thing. I don't know if this is related. I have done everything I can think of but I'm now very frustrated.
I think I have mentioned everything that I can think of. Any suggestions would be welcome.
Thanks a lot,
Eric