1. Usually browser hijackers are installed by unsafe freeware, shareware or advertising-supported programs such as various browser add-ons or toolbars. Even some reputable products’s Instant Messenger can change default web browser settings. Uninstalling the host application in most cases doesn’t remove bundled parasite.
2. Lots of spyware and adware parasites have integrated browser hijackers that get silently installed during the host parasite’s installation process. Removing a particular spyware or adware doesn’t affect a browser hijacker.
3. Some widely spread browser hijackers get into the system using Internet Explorer ActiveX controls or exploiting certain web browser vulnerabilities. Their authors run insecure web sites (mostly with pornographic or illegal advertising content) filled with malicious code or distribute unsafe advertising pop-ups. Whenever a user visits such a site or clicks on such a pop-up, harmful scripts instantly install a parasite. A user cannot notice anything suspicious, as browser hijackers do not display any setup wizards, dialogs or warnings.
So dear readers now you have realized that if you don’t do this you are safe from Browser hijacking.(Source www.2-spyware.com)