Each computer has a special HOSTs file to store the web addresses. This file can be used in certain cases to speed up access to the web pages you tend to visit more often. However, sometimes this file is abused by malware. If this is the case, you might need to try the option of resetting the HOSTs file by clicking the “Tools” menu, selecting “Reset browser settings” and ticking “HOSTS file“.
The Windows HOSTS file is a text file that stores website addresses. The file can be used to speed up access to websites you often visit – by equating the website name (e.g., microsoft.com) with its DNS address, the web browser can find the website more quickly, as it does not have to query a DNS Name Server.
Some Malware programs add entries to this file to either deny access to websites (usually security-related or antivirus company websites) or re-direct access to their preferred websites.
There should be only one line in the “hosts”: 127.0.0.1 localhost in Windows XP and 127.0.0.1 localhost ::1 in other Windows versions. If there are more, then remove them and save changes. Read more about Windows Hosts file here: https://support.microsoft.com/kb/972034