In internet explorer select "Tools" from the Menu Bar and then "Internet Options", the the "Connections Tab", then the "LAN settings" button clear all check boxes and OK your way back out of there.
Look at this file C:\Windows\System32\drivers\etc\hosts
remove all lines not preceeded by a # sign and save (may have to remove the read only attributes under file properties)
Download, install, update (signature files), SpyBot Search and Destroy and Malwarebytes. Reboot the machine in safemode and run both (Malwarebytes "Full Scan"). Remove anything they find.