How to remove Ask.com toolbar?

I'm using Firefox on windows 7. I have unknowingly installed Ask.com toolbar and now I don't find any way to completely remove this new search engine. I have set "Google" as my default search engine and "Google.com.pk" as my default webpage, but whenever I open a new tab, Ask.com appears from nowhere.

I also tried this step: Go to address bar and type-->>about:config-->>keword.URL (right-click and reset it)-->>restart Firefox......but nothing happened. Ask.com has still hostaged me.

Please let me know how to get rid of Ask.com?

Regards

via Bleeping Computer Last 20 Posts http://www.bleepingcomputer.com/forums/t/509211/how-to-remove-askcom-toolbar/