[irfan.sanober@xxxxxxxxxxxxxxxxx]

Step 1:
At command prompt
ping 4.2.2.2
if successful goto next step otherwise
run
tracert 4.2.2.2      
   (and post your result)

Step 2:
nslookup www.yahoo.com 
if successfully resolved goto next step
otherwise Change your DNS to Service provider DNS or universal dns like
2.4.4.4

Step 3:
ping www.yahoo.com
if successful go to next step, otherwise
try to connect internet with different method like Dialup or via some friend
wifi internet connectivity.

Step 4:
try to browse www.yahoo.com form your
internet explorer
if not successful install some other
internet browser like firefox.

please let us know your Findings...

Hope thats help

Thanks & Regards

Mirza Irfan Sanober