Check your router DNS setup, try these [OpenDNS][1] DNS servers:

> 208.67.222.222 (primary)

> 208.67.220.220 (secondary)

And the same for you NIC config.

try to ping to an IP adress ie: 66.102.9.103 (this is google one) to see if this is a DNS related problem.

[1]: http://www.opendns.com/