Delta Search is a third-party toolbar. It can be considered malware as it simply piggybacks on Google's normal functionality while changing the browser's home page, altering search results and delivering advertisements.
Delta Search Toolbar is published by YHS and is often installed along with other software, sometimes without proper notification or the user's awareness of it. Delta Search can be removed manually by following the software uninstall procedures for each version of Windows. Traces of it frequently need to be removed from Internet Explorer and other web browsers. Antivirus programs do not block or remove it, but a third-party malware removal program may simplify the process of uninstalling it.