Yesterday, I got some work fixing a PC that was loaded with trojans. After a repair installation of XP Pro w/SP2, I was brought to the activation window which could not hit the internet.
Thinking the problem was a driver issue, I quickly pulled the Windows key + U trick to pull up an explorer window. Finding the drivers were intact, I proceeded to both ping 4.2.2.2 & google.com, as well as nslookup google.com. Both were successful.
I opened an IE window, checked the proxy settings, reset all the settings, etc...still could not browse--was getting the error:
Internet Explorer can not open the search page."
As well as a page cannot be displayed error.
Thinking the trojan was still impacting IE, I installed Firefox from a flash drive, and ended up with the same result.
I next attempted to telnet to port 80 & 8080 on a number of web sites. All HTTP traffic was blocked.
After a few more hours of struggling & research, I realized the culprit:
Norton Internet Security Version 2006 (Symantec).
A run of the Norton Removal Tool (http://service1.symantec.com/Support/tsgeninfo.nsf/docid/2005033108162039) & reboot, and the issue was resolved.