After upgrade to 29.0.1 unable to use any search engine - keyword.enabled is set "TRUE"

Further to above have being doing more tests on this and it would appear to be the Plug ins which are possibly causing this problem. However, it is very "hit and miss" and inconsistent if I disable all add-ons sometimes it works other times it doesn't. Starting in "Firefox Safe mode" - from Help tab usually works, disabling all Plug-ins manually gives inconsistent results. Have reverted to using Chrome if I need to use a search engine as this is so annoying. I repeat this has only ocuurred since updating to v 29.0.1.