can you do following - after reboot but before you launch any browser.
- check content of /etc/resolv.conf after the boot and ensure it contains proper nameserver definitions
- run ping to each of the mentioned there nameserver
- run
dig www.aljazeera.com - run
curl -v http://www.aljazeera.com/ - finally open the browser and ensure behaviour is consistent. Eg if curl works and returns content - browser should show the page as well. If curl gives error - browser may give error as well, or may actually display the page.