If a program installs toolbar for Firefox and  hijacks search engine and homepage of browser then you don’t need to manually fix them, just click on Reset Firefox button and it will remove toolbar crapware and restores browser to factory settings. When a program outside Firefox tries to install an add-on to the browser Firefox blocks it and alerts you with a dialog about the same. Some add-ons still sneak through and changes browser search and homepage preferences without user consent. Here Firefox users forgetting the strong built-in feature “Reset”  button introduced with Firefox 13. 

Reset Firefox is the mantra to remove toolbars and Undone Search engine and homepage changes caused by adware/malware

1. Go to Firefox>Help>Troubleshoot information

2. Click on Reset Firefox button.

Reset feature axes toolbars, resets Firefox settings to defualt

Following changes will happen to Firefox

Saved items: Your browsing history, bookmarks, passwords, Cookies and Plugins will be untouched they will be saved and moved to new profile.

Which will be removed?: extensions, themes and toolbars

Search engine and homepage will be reset to default.

Resetting Firefox does no harm, additionally brings newly installed Firefox felling and zippiness to browser by ditching crapware. You should use it more often in future. Why are you forgetting this tool?