Welcome to Anvisoft forum. Thanks for posting your problem here. I am Ivy and I am going to help you with your problem.
The delta search can be remove easily with the free utility Anvi Browser Repair
developed by Anvisoft. Anvi Browser Repair
will help you conveniently repair browser settings and networking settings such as homepage, safe startup items, DNS settings, Title Bar, BHO plug-in, etc, changed by malware to return smooth browser use.You can download the free tool directly via the link: http://www.anvisoft.com/software/brt/
After you download the tool, please start the tool and click "Fix" button, then your problem will be solved. Please note that, some of the features only take effect after your computer is restarted.
Meanwhile, I would like recommend you clear your browser cookies with Cloud System Booster. Cloud System Booster download: http://www.anvisoft.com/product/cloudsystemboosterpro.html
If any problem, please let us know. We are always glad to offer help.