How do you connect to the net? Do you have a dsl or cable modem alone or do you have a wired or wireless router in front of them.
Reboot whatever it is.
If problem persist, you may want to read this:http://support.microsoft.com/?kbid=299357
If the url with a ip address did not work, you probably have worse problems than dns lookups failing.
type this in at the command prompt:
telnet 126.96.36.199 80
If you get a blank screen type "GET" and hit enter
That's all caps and without the quotes.
You should get a recognizable html source page for google.com
If you don't, you don't have have a working network connection since that would work even if you had no dns resolver at all.
Do you have any working computers on the same network device? (Just to make sure we are only dealing with this single computer.) Does it have the same dns servers listed at the ipconfig /all screen?