Wrong URL redirecting to search engines for all browsers (yahoo in my case)

I am getting a strange error first time. Whenever I enter a wrong URL/domain, it redirect me to following link:-

http://in.yhs4.search.yahoo.com/yhs/errorhandler?hsimp=yhse-001&hspart=CND&type=A0196687591F04C1AACF_s_g_e&q=http://localhost:3000/wrongurl

I searched over internet but did not find any positive solution.

I have tried following for firefox browser:-

1. Reset Firefox in safe and without safe mode
2. change about:config >> keyword.enabled (not found keyword.URL in my system as everywhere mentioned)
3. change internet options of windows like default search etc
4. Virus scanned with MS Essential updated version

I also restarted firefox and system but still getting the error. Because of this error, I am unable to see errors while web-development and gone to log file again and again.

Please find the solution if anyone faced this problem ever.

Thanks.

I finally fixed the problem. This is because of conduit search that was automatically installed in my system while installing a software. Initially I was failing because of removing all services names with yahoo as I was redirecting to http://in.yhs4.search.yahoo.com. But in actual, this yahoo search was internally associated with conduit search.

Then I tried to remove conduit search service, it automatically removed redirection to yahoo search.

Now I can get errors on my developed web pages if they are (with redirection).

@Paul/@Rob : Thanks for your help.