To Remove Ask, do the following:

1. Click on Start, then Control Panel. Go to Add or Remove Programs. Uninstall anything related to Ask.
2. Then, Update Firefox to Firefox 15. Update Firefox to the latest release
3. After doing that, install https://addons.mozilla.org/en-US/firefox/addon/searchreset/
4. Finally, if that fails, try to Reset Firefox. Refresh Firefox - reset add-ons and settings

Reset the browser.startup.homepage:

   Open the about:config page via the location bar
   Type in the Filter bar: browser.startup.homepage
   Right-click and select Modify
   Enter: http://www.google.com/search?q=
   Close and restart Firefox 

   You can also reset: keyword.URL to the same.