Doko search on google chrome

I have recently used Google Chrome to find that when loaded it displays doko-search, on checking to see if this is a legitimate search engine my web results show that its is spyware.  I am unfortunately a technophobe and not very knowledgeable about computers so I have found it difficult to understand the solutions these web results have provided, I have norton 360 installed and have recently done a full system scan, however doko search still appears.

I would be very gratefully for any help or advice in how to manage this.

Thanks in advance.