Google what?
Sorry. Google “host file hijack fix” or “host file redirect fix”.
There is a file with no extension at
C:\WINDOWS\system32\drivers\etc\Hosts
that can be opened and edited using Notepad. It can contain hardcoded paths based on domain names and partial url addesses, and instead direct anything to a specific IP address rather than looking up the IP address at a public DNS server.
I don’t know if DigitalVideo is right that this is your problem, but it won’t hurt to open the file and delete any lines from the bottom that do not begin with a # symbol.