The white screen/black screen could be caused by older versions of RealNetworks software. See this article for more information: Flash 11.3 doesn't load video in Firefox. Does that help?

I have tried those 'solutions' and Flash continues to crash. I removed Real Networks entirely and reloaded Flash. Still doesn't work. Isn't it time to admit there is a problem with 16.0 and fix it? Remember, I'm on XP-Pro

Sorry, you didn't mention crashes, so I only addressed the problem you described...

On some systems, graphic card driver incompatibility creates problems. This is not a new issue in Firefox 16, but since other software may have updated recently, I think it's worth checking.

To disable hardware graphics acceleration in Firefox and in Flash

(A) In Firefox, un-check the box here and restart:

orange Firefox button or classic Tools menu > Options > Advanced > General > "Use hardware acceleration when available"

(B) In Flash, see this support article from Adobe: http://helpx.adobe.com/flash-player/kb/video-playback-issues.html#main_Solve_video_playback_issues

You usually need to restart Firefox to see the effect of these changes.

If that doesn't help, could you perform the following test: try a problem page in a new Firefox profile. In addition to bypassing current add-ons and custom settings, a new profile should have completely fresh settings databases and a fresh cache folder.

Close Firefox and start up in the Profile Manager using

Start > Run > firefox.exe /ProfileManager

This dialog displays your existing profiles (at least the default, possibly more) and allows you to create news ones and switch between them. More info: Profile Manager - Create, remove or switch Firefox profiles.

Create a new profile, accepting the defaults and using an applicable name such as "Fx16 Clean" and restart Firefox in the new profile. The main difference is that you will not have any extensions, bookmarks, or other customizations.

Does Flash work in the new profile?

YES - The problem likely is associated with an extension or custom settings in your normal profile.

NO - If Flash still doesn't work correctly in the new profile, we would need to consider other factors. You might try disabling other non-Adobe plugins using this page:

orange Firefox button or classic Tools menu > Add-ons > Plugins category

Next Steps

You can use the Profile Manager to switch back for further troubleshooting. Alternately, you can:

• Manually migrate settings to the new profile as described in this article: Recover important data from an old profile.

• Have Firefox build a new profile with automatic partial settings migration using the Reset feature. You must first restart in your normal profile to do this. More info: Refresh Firefox - reset add-ons and settings.

I think I'm losing it!

I did not have time to try any of the suggestions you made in your last reply. But, after the computer had been shut down for several hours, I restarted and the flash videos played OK. To the best of my knowledge, not updates to either XP-Pro, Firefox of any of the plug-in's had occurred unless there was still something pending when I had shut down.

Last evening, without further intervention, the videos played OK. Same for this morning.

I hate problems that mysteriously disappear!!!! Do you have any idea what has been going on? Is it something related to XP-Pro?

I guess the problem is solved... at least for the present. BTW, Real Networks is still uninstalled; I don't think I need it.

It is possible that your firewall was blocking the plugin-container process and that an update has fixed this.