Google instant is a function of the Google site which you can access by clicking on the "gear" icon at the top right of Google's home page. The gear icon takes you to an advanced search where you can set your preferences for using Google instant.

For searching from the Firefox address bar, please see the support article on Location bar autocomplete:

https://support.mozilla.com/en-US/kb/Location%20bar%20autocomplete

and the article on smart keywords at:

https://support.mozilla.com/en-US/kb/Smart%20keywords

The functionality in Firefox has changed some. Sometimes people type in a keyword and make a typo, and can then be directed to an unwanted page. The new functionality helps to keep that from happening, and it helps with security.

You might find the information at:

https://support.mozilla.com/en-US/kb/Location%20bar%20search

to be helpful to you, as it shows you how to disable the default keyword search behavior that gives the results you are describing.

To use the feature, you should use <domain name> <subject> for the lookup to work best. E.g., espn football

If this answer has solved your problem, please mark the question as "Solved". This way you will help others in a similar situation.

Start to type. As you type a search on Google, the homepage automatically starts displaying your search results -- no need to press Enter

i want this and with internet explorer i see it

Did you try

     https://encrypted.google.com/preferences?hl=en

and are you allowing cookies from Google?

I deleted firefox and installed it again.

and now it works!!!

let's see if it happens again to know what caused it