GIGASearch is a hijacker that also installs a Browser Helper Object (BHO) onto Microsoft’s Internet Explorer Toolbar, ShellBrowser and WebBrowser.   This nuisance will also take the opportunity to commandeer your Internet settings and change your search queries.  In addition, this program will deliver advertising by means of pop-ups, pop-unders, etc. to your desktop.
Your computer will soon lose some of its original functionality.  It will slow down and not work as efficiently as it once did.  This malware is harmful and should be removed from your computer as soon as possible.  It is important that you find a reliable anti-spyware program like ZookaWare PC Cleaner to remove this problem from your computer as soon as possible.