/$ sudo apt-get --reinstall install firefox
Reading package lists... Done
Building dependency tree... Done
Suggested packages:
  firefox-gnome-support latex-xft-fonts libthai0
The following NEW packages will be installed:
  firefox
0 upgraded, 1 newly installed, 0 to remove and 94 not upgraded.
701 not fully installed or removed.
Need to get 0B/9218kB of archives.
After unpacking 29.3MB of additional disk space will be used.
(Reading database ... 131368 files and directories currently installed.)
Unpacking firefox (from .../firefox_2.0+0dfsg-0ubuntu3_i386.deb) ...
dpkg: error processing /var/cache/apt/archives/firefox_2.0+0dfsg-0ubuntu3_i386.deb (--unpack):
 trying to overwrite `/usr/bin/mozilla-firefox', which is the diverted version of `/usr/bin/mozilla-firefox'
Errors were encountered while processing:
 /var/cache/apt/archives/firefox_2.0+0dfsg-0ubuntu3_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)