It is a browser hijacker.
Step 1: Open your Task Manager by pressing Ctrl+Alt+Del. Then end the related process of Isearch.fantastigames.com/440.
Not there, doesn't seem to exist.
Step 2: Reset your browser settings. (Take IE as example)
Open Internet Explorer. Click on the Tools menu and then select Internet Options. In the Internet Options window click on the Advanced tab. Then click on the Restore Defaults button and then press OK.
Did that already, several times, doesn't help. If you go into Internet Options in Control Panel, it states that the default is Google, but once you bring up Internet Explorer, it still redirects to Isearch.fantastigames.com
Step 3: Search and delete following files.
Can't seem to find these either, don't seem to be in my system.