Found this for Babylon but I suspect it will work with Delta.
If Babylon pages are opening up each time you start up Chrome, check in Chrome menu (previously Wrench icon) > Settings > On Startup > next to the radio button for Open a specific page or set of pages, click on Set pages > remove any unwanted URLs by hovering over the URL until you see an "X" appear to the right side of the URL.
If all searches that you perform in the are returning with results from Babylon instead of your preferred search engine, check in Chrome menu (previously Wrench icon) > Settings > Search > Manage search engines > check the list of Default search engines, Other search engines, and Search engines added by extensions, and remove suspicious entries that you are not familiar with. Depending on your extensions, you may not see the last section for Search engines added by extensions.
If Babylon is opening up when you click on the Home button, check in Chrome menu (previously Wrench icon) > Settings > Appearance > select the Show Home button checkbox > check if the URL that appears below it references Babylon.
Also check that there are no extensions installed that may be causing these changes. Go to Chrome menu (previously Wrench icon) > Settings > Extensions > if you see any unfamiliar extension that you do not remember installing, try disabling/removing the extension to see it was causing these changes. To disable, uncheck the "Enabled" checkbox next to the extension. To remove, hover over the extension until you see a trash can icon appear, and click on the icon.