I notice in your "More system details..." list that you have two versions of the Flash plugin. Can you delete everything but the latest? This thread has some guidance on that, although it refers to the folders in Windows 7 rather than Windows XP, it's similar: flash works fine in firefox 14 but i can't update it.

That probably won't cure it, but might help.

There are some compatibility issues between the latest Flash player and some Firefox add-ons or settings. Could you see whether anything in this article helps: Flash 11.3 doesn't load video in Firefox.

You might also consider disabling the new protected mode in Flash 11.3, since that feature is currently being debugged. See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

I copied and pasted the same version. I only have one versin installed

I did as you suggested. Only 1 version installed, removed protected mode, still same crap.

This was never an issue before mozilla changed the cahching features of ff. The plugin-container.exe has more issues than is helpful!

Now it looks like chrome is hooking into your code structures, adobe is doing everything to prevent ff from functioning.

Get this right, I am getting fedup with thi messing around and always fighting a browser that used to rival M$, now you're just as bad.

IT DON'T WORK!

I appreciate your frustration, but the support volunteers here are not developers. If we can identify a particular reason for the problem -- a setting, another add-on, etc. -- then you or one of us can file a bug for it. I don't think we've nailed it down just yet.

Could try the new Reset feature? This duplicates certain key data from your active settings folder into a new one, bypassing some add-ons and custom settings. Your plugins (including Flash will still be active).

More information in this article: Refresh Firefox - reset add-ons and settings.

If the new settings folder (AKA Firefox profile folder) has the same problem, you can switch back if you like using Firefox's Profile Manager. (This article describes how to start Firefox in the profile manager. I do not recommend removing anything until you are 110% certain that you will never need any of that profile's data in the future. Profile Manager - Create, remove or switch Firefox profiles)

Notice any difference?