Go to start- all programs -accessories- Command Prompt.

In the command prompt type ipconfig/renew

Try your internet.

If it does not work paste the information from the ipconfig/renew in this fourm please

Hope this helps!!

Also do you have antispyware? If you dont you should get some. Spyware could hve changed your hosts file. I have AVG antispyware- You get it at free.grisoft.com