Its a search engine hijacker. Check this website for removal: http://www.techsguide.com/how-to-remove-palikan-com-search-bar-removal-guideline/.

sunny-

Have you clicked on any popup windows recently that looked legitimate (but may not have been)? Or have you downloaded any free software lately, say a game, or a screensaver, or a ringtone, etc.? This type of malware is frequently the price you pay for "free" stuff.

It is a malware that is called browser hijacker. It overrides your browser and remains until you remove it. To get rid of it completely it is better to use an antimalware program. Try running a scan with Antimalware Malwarebytes. It’s a free and quite reputable program that will be able to remove the hijacker automatically requiring minimum of your interference.

http://www.free-uninstall.org/how-to-uninstall-remove-palikan-com/

Ah SPAM, it's what's for lunch!!