I'm running Mepis v6.5.02 with KDE which came with Firefox v2.0.0.3. I've downloaded and untared v2.0.0.5 but don't know how to install it. The file doesn't have an Install file explaining how to run it. Thanks.

The file you downloaded, is a prebuilt binary. All you need to do is extract the contents of the file, navigate to the extracted directory and run firefox by clicking on the file/icon named "firefox" or if using the command line, do "./firefox".

I tried that, it just loads the old 2.0.0.3 version.

Any shortcuts you had are still pointing to the old version, if you want to keep the one you already downloaded you'll need to change those.

Probably a better way to upgrade is to use your package manager. From a command line you need to switch to root, then type apt-get update then apt-get upgrade. There's also probably a graphical updater, probably synaptic.

I've corrected my post. I did not mean that you click on the Firefox icons in the menu or desktop shortcuts. I meant the icon labeled Firefox in the directory that you get when you unzip the firefox tar.gz file.

The extracted version should work just by clicking on the firefox (or firefox-bin?) file from inside the directory extracted, like said, but in some cases it won't start because it can't find the library files; this is because on some systems it won't search for them in the current directory, so if you don't have Firefox already installed, the needed libraries are not in the system library directory, and if they're not searched from within the parent directory, the program won't run. A complicated explanation, but hopefully you'll get it. Another thing is that if the (older FF's) libraries are in the system library directory and you start FF from the extracted directory, it might find the (older) libraries first (or only) and use them, in which case I'm not sure how well it works.

One option is to copy the library/other files from the extracted directory to their "correct" places on the system, but it makes removing the program more difficult (tracking the files that are copied manually). Nowadays it hopefully just searches for the libfiles (and possibly others needed) from within the launching directory, so this problem doesn't exist; not sure, haven't tried.

A primary way to install a new Firefox should be by installing a binary package meant for your distribution, because it makes upgrading and removing it a lot easier later on. For Mepis you would need to get a .deb file, but since Mepis is a fork off Ubuntu I believe, you could do with an Ubuntu Firefox .deb file too. I'm fairly sure the Mepis/Ubuntu reposities (Mepis uses Ubuntu reposities, or does it?) have a newer version of FF though (not necessarily the newest 2.0.0.6 yet), so try there first with apt-get / Synaptic like said.