Since update I can not access add/remove, downloads, Firefox, or help on ubuntu OS.

I have never heard of this til now. It might be a stuck package? You can try booting into recovery mode by hitting the esc key at boot time and selecting the top line that ends in "recovery mode" then af the next menu select "fix broken packages". Did you have Firefox 2 and 3 installed or just one of them? Is Firefox running in gnome system monitor after you start it and maybe just not showing the window? The only other thing I can think of to try would be to make a new user and log into that user and try it.