Your computer hardware is getting to the stage where most software needs resources your machine cannot provide because it is too old. You have a couple of choices.

1. Get newer hardware that can handle the newer software
   
   
2. Use a different operating system, like Linux (which is free)

I refurbished an old G5 recently and it runs the newest Firefox just fine. I put Lubuntu on the machine in place of the MacOS. Lubuntu (pronounced Loo-boon-two) is sort of an Ubuntu lite - a user-friendly version of Linux. There are many applications to choose from, and it's all free.

You can also use the more resource-hungry and slightly friendlier Ubuntu, also free, but you may be happier with the performance of Lubuntu instead.

The PowerPC I did this on was one of the old Bondi Blue ones. Firefox 8 had no problem running on it at all and has all plug-ins needed for video, audio, etc.. I gave it to a church and it's running fine for them.

You can download old versions of Firefox, but you'll just open yourself up to security problems if you do.

FYI: The Mac operating system is built on Linux.

This doesn't answer my question. Why? Why does Firefox not allow me to continue using the versions I was using? It was working fine, Who are they to decide for me, security issues? Who are they to disable my plugins? Is this how they force consumers to buy new hardware? I am not happy with this action that they have taken without any communication with me. You offer two choices, one I can't afford, and the other I have no idea how to accomplish.

Browser security affects not only the user who is using the browser, but others as well: you are part of a larger community rather than an island to yourself.

Software and hardware have a co-dependent and symbiotic relationship. They each depend on the other in order to function and evolve.

When software evolves (improving security, subtracting bugs, adding functions, etc.), older hardware cannot always handle the newer software and needs to be upgraded.

When hardware evolves to take advantage of newer software, it adds capacity, which software then eventually uses up and the cycle begins anew.

When old software is retired because it is no longer effective in addressing the needs and desires of its largest user-base, new software is written to address those needs, and the old software is no longer used. This is why you are using Mac OS X 10.5 instead of DOS. It is also why there are now many choices for computer users that did not exist 10 years ago.

It can be a pain to have to adjust to change, but all things living must eventually die, and all things pass away in the fullness of time.

It is clear as day Firefox does not support MAC G5 non-Intel based computers on cue with Apple's intent to phase out system within 5 years of purchase. They are forcing us to get new machines and that's the bottom line.