If your fun of watching trending video from networking site and asked you to install an application, this is probably a virus. It will redirect all your website including Facebook.com, YouTube.com and Google.com to “gateway.zscaler.net”. Then will asked you to enter username and password, similar to the below screenshot.
In order to get rid of this problem, follow the instruction below.
1. First, Open Control Panel
2. Then, find Internet Options
3. Then, click the Connections tab
4. Then, click the LAN Settings button
5. Finally, Uncheck the Proxy Server
It works on both Windows XP and Windows 7.
This are just some of the virus spreading all over the net. So make sure to verify the link before clicking it.
Hope this will fixed your problem.