It's possible that the search engine link is not correct. Try using the Restore Default Search Engines button in the Search section of the Firefox settings.

You may also want to make sure that you have the Automatically update search engines option checked in the settings so that, if there are any future changes to the Google search link, it's applied to Firefox automatically.

Hope this helps.

thanks for your reply! i tried your suggestions but the restore default search engines is grayed out in Options and the automatically update search engines is already selected....

If it's greyed out, that usually means that you are currently running the default search engine configuration. Try removing Google from the list of search engines and then press the Restore Default Search Engines button. See if that helps.

If it doesn't help, see if the search functionality is working properly in Firefox Safe Mode. There could be a browser extension or other program that is interfering with the search feature.