I can't log in to gmail (I know my password and user name), the ...

I can log into gmail via Microsoft's Internet explorer so I know that my user name and password work. I have also added www.google.com to the list of ...

I can log into gmail via Microsoft's Internet explorer so I know that my user name and password work. I have also added to the list of allowable web sites in Firefox. The google account was started about two weeks ago and I had no trouble logging in until about 3 days ago. I have gone thru all the recovery steps suggested by google. I suspect that there is something between Firefox and google that needs fixing, but I do not know what.