Try modifying the string of keyword.URL to "http://www.google.com/search?ie=UTF-8&oe=UTF-8&q=" without quotes.

Hope this helps

see https://support.mozilla.com/en-US/questions/850287

If the link solves your problem please mark this one as solved.

Open the about:config window and change these settings:

• browser.search.defaulturl - set to http://www.google.com/search?num=100&q=
• browser.search.defaultenginename - set to Google

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

• https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes

ahnasr: thanks a lot, this is what i did in the end but it bothers me that the default has changed to something else; which is probably an add-on / extension that i used and even though i removed it, it still remains somewhere in the configuration. finitarry: yes, the browser.search.defaultenginename was set to yahoo search, so i changed that but there was no browser.search.defaulturl to change -which is ok, right? cor-el: i'll try the safe mode again and follow your recommendations.

browser.search.defaulturl is not part of Firefox and resetting it would make it disappear. In my answer, I did specifically mark that as okay if it didn't exist. It was probably created and used by the Yahoo toolbar to make changes to the keyword.URL which is what is used in Firefox and was getting reset to point to Yahoo. (configuration variables are case-sensitive).

thanks to all who helped! multiple things are working, do i have to select only one "solution"??

You can change the default engine name and the keyword. That should restore things back to normal. Actually, resetting those should return things to normal.

https://support.mozilla.com/en-US/kb/Search%20bar?s=bing&as=s

thanks to all who helped! multiple things are working, do i have to select only one "solution"??''

Yes, as owner only you can mark as solved and you can only choose one answer for that so try to choose the best answer. Anyone can register any answer as helpful or unhelpful which like a solution does not require a comment. You are not the first to find out until afterwards.

Fortunately there weren't any registered as unhelpful but such answers could mean anything from off-topic to good answer for another question but not mine and does not does get a better answer or understanding for anyone without a comment.

If a solution has multiple suggestions it should be made clear which parts helped so people can concentrate a bit on alternatives or on emphasizing most likely portions to be of help.

Make sure you don't have something called "Conduit engine" installed. It is installed with some toolbars and allows you to install "apps" on your browsers toolbar interface. It also resets your "browser.search.defaulturl" and "keyword.URL" settings to redirect keyword searches in the address bar.