Difficulty in accessing the internet after an Ubuntu update

I just got the Ubuntu Update (10.04 (lucid) GNOME 2.30.2 and Kernel 2.6.32-30 generic, GCC version 4.4.3.) and I have started using it. However, a time came wherein I experienced difficulty in accessing the internet. The message in the dialogue box would say, “Can’t find the server.” Sometimes, however, when I click the Try Again button, it would work. It is really annoying for me since I need to try it over and over again in order gain access to the internet. I have never experienced this before using the 4.10. There is also another message which says: “Ubuntu cannot find the server.” I wanted to go back to the previous settings, but then I don’t know how. Please help me. Thank you so much.
