This will be the form history. See the form autocomplete article for details of how to clear the form history, plus if you want, how to prevent Firefox from remembering form history.

Do you mean searches via the Google Toolbar?

http://www.google.com/support/toolbar/bin/answer.py?hl=en&answer=9271

Yes and no. I can clear recent history in the google toolbar .I also use windows and mostly cc cleaner to cleanout everything.It is somehow still in memory because if i use another website search or the google toolbar in the middle of the home page i will get other words poping up as soon as i start typing a new search.They are all related to old prior searches.

Thanks for all the help Problem seems to be solved.