go to
<root drive>:/windows/system32/drivers/etc
your root drive is mainly C but if you have multiple drives it could be anything.
Once in that folder there is a file named hosts you need to open it with notepad and make sure that there are no lines that dont start with a #. Some programs that you install make these host file entries because they are the first step in resolving names (turning names like login.playrohan.com into an IP address)