IE and Firefox can't connect to internet

I am attempting to troubleshoot wife's HP Pavilion laptop, which stopped being able to access the internet via Internet Explorer a couple of weeks ago.

Symptoms:

In IE, attempt to open any webpage, get a "Internet Explorer cannot display the webpage" error. Click on the Diagnose Connection Problems button; depending on the URL entered, you'll either see a Windows HTTP error message 403 (Forbidden), or a "Windows did not find any problems with this computers network connection".

Cable modem & router believed to be OK as I am able to access interent just fine on my XP PC. Her laptop also does have some degree of connectivity - little green & yellow blinky lights next to network cable plug blink reassuringly, laptop is able to receive MS Windows Updates and weather updates on desktop gadget. In command mode, am able to ping google 74.125.67.100 successfully.


Remediation attempted thus far:

All the suggested troubleshooting steps in MS article http://support.microsoft.com/kb/956196.
1. Try viewing other web pages.
2. Run Network Diagnostics tool in IE. It did not find a problem to fix.
3. Reset modem or router. (Done MANY times now)
4. Use Delete Browsing History feature.
5. Try IE with Add-ons disabled.
6. Disable (Windows) firewall.
7. Tested IE in safe startup mode.
8. Check whether 3rd party service is causing conflict by disabling all services in msconfig.
9. Use Device Manager to verify that the network adapter is working correctly. No exclamation marks indicating trouble found
10. Reset IE settings on Tools > Internet Options > Advanced tab.

Tried upgrading IE 7 to IE 8.

Tried installing Firefox 3.5. .

Tried doing System Restore to a date going back several months ago. (System has been restored back to current date/time).

Ran SFC/SCANNOW. Found corrupt files, but was unable to fix some of them. Could not open the log file to see what got fixed and what was not. (Access denied?!? - gawd, I hate Vista. This experience has firmed up my resolve to keep my old XP desktop going as long as I can!)

Tried netsh winsock reset in command mode.

All of the above have been unsuccessful.



Other shreds of info:

Problem exists whether using wireless mode or wired.

OS is Windows Vista.

There may have been a trial version of Norton Internet Security that was preloaded, but has since been removed? - It doesn't show up in Add/Remove software list, but there was an empty folder with that name in the Start menu, but she does not recall removing because of purchase nag messages, so don't know what to make of that.

Simply don't know what triggered the change for IE to stop working.


Would appreciate any troubleshooting tips!!! Thanks for you consideration!

 

try this in a command window
netsh winsock reset catalog

 

Geminiione - tried your suggestion, unfortunately did not work, but thank you for taking time to try and help.

DomLuc - Ran the Norton removal tool twice as suggested and that fixed problem - YEEHAA!!! Gawd, I lost track of how many hours I spent trying to figure this out, so many many sincere THANKS!!! :celebrate This site is truly the best!