IE and opera won't open web pages

Hi!

I have a problem with my internet connection. We have 2 laptops at home both use XP and on one computer everything is working fine. On the other, when i connect the internet cable to it, then it showa that internet is connected but neithet IE7 or Opera open any web pages. When I disconnect the cable and connect through wireless connection then everything works.

I don't know if this has everything to do with it but the problem started after I had installed Avast antivirus. I installed it in the evening and then turned off the computer. When I turned it on the next morning then web pages wouldn't load.

I hope someone can help me with this.

What firewall are you using? What other security? Are you using multiple security brands on same computer?

I'm using Windows firewall. I used Avg 7.5 then updated to Avg 8 but it had problems - it didn't start scanning computer for viruses, so I uninstalled it and installed Avast instead. Since after that I could not access web pages I uninstalled that too and now I have Avira antivirus installed.