Go to C:\Windows\System32\Drivers\etc and you should see two files, one called hosts and localhosts or lmhosts, make a copy of these and drag them somewhere safe (just in case). Once you have them backed up somewhere else, not in the same folder preferrably, delete them, and then reboot your computer. Windows will rebuild them upon reboot.
127.0.0.1 is a loopback on your network adapter and nothing more.
If you're not comfortable doing all that, go HERE
and follow the directions.