Hello J.

Yes, Flash tends to do that sometimes, for some users. Thankfully Firefox 3.6.4 (the next update for Firefox 3.6) will not crash when a plugin crashes, which is very good!

Meanwhile, you may want to make sure all your add-ons (plugins, extensions, themes and all) are up to date. To manage add-ons go into Tools > Add-ons. It's fairly straightforward. If they are, or if updating them doesn't fix it, you may be having a problem with some Firefox add-on that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons (just to check), to see if Firefox goes back to normal?

Whenever you have a problem with Firefox, whatever it is, you should make sure it's not coming from one of your installed add-ons, be it an extension, a theme or a plugin. To do that easily and cleanly, run Firefox in safe mode and select Disable all add-ons. If the problem disappears, you know it's from an add-on. Disable them all in normal mode, and enable them one at a time until you find the source of the problem. See this article for information about troubleshooting extensions and theme. You can troubleshoot plugins the same way.

If you want support for one of your add-ons, you'll need to contact its author.

Like I said, Safe Mode does not prevent the crash. And in the last 2 hours of watching streaming Flash, it crashed something like 20 times. Safe Mode with add-ons disabled or not.

I know safe mode did not prevent the crash, I mean safe mode with all add-ons disabled. Of course since you're disabling all add-ons, you'll also disable Flash, so this will only tell use that add-ons are the source of the problem if safe mode with all add-ons disabled doesn't crash. If this happens, it's likely that it's an issue with Flash. Try disabling all add-ons (manually, this time) except flash and see if the issues persist. If they do, you need to contact Adobe, since it's their software.