sounds like your hosts file has been compromised. I would recommend creating a second user with admin access and opening up the hosts file in notepad [launch notepad with admin rights and nav to C:\Windows\System32\Drivers\etc].
open the hosts file and make sure the last three lines look similar to this
Code:
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
if not... nuke everything below the above pasted code