1- Remove Babylon Toolbar ,if you have it installed. The most complete removal is to remove it from your system using (Windows) Control Panel > Add or Remove Programs
2- Reset to the default by clicking Restore to default on Options > General > Start up > Home page. Be sure to set When Firefox starts to Show my home page on that same panel.
3- Reset your Location Bar search engine using below method:
Type about:config in your Location Bar, like typing a web site address, and press the Enter key ignore warning and choose to next. In Filter, type keyword.URL In lower part of screen, if it is bold and shows user set, right-click keyword. URL and choose Reset in Filter, Type Babylon any items in lower part of screen in bold and showing user set, right-click and choose Reset Close about:config tab Restart your Browser