web browsers not working but messengers, thunderbird working

For the past several days, I have this network connection problems with my laptop: I can not connect to interent use any of the browsers but my windows live messenger, thunderbird mail client seem work well.

The wireless connection or ethernet connection all tell me it is connected either using wireless or using cable plug-in directly into my laptop.

I donot have third party firewall and enable/disable windows firewall does not solve a thing. When I use IE 7’s diagnostic to test, it gives me result that there is no connection problem: ftp (passive), http and https all work well.

I was so confused and do not know what is going on? Is there due to the reason that some services are not started or some other reasons? Please help.