Having Flash Player up to date is one part of the battle. The other is Shockwave. If you do interactive stuff like Facebook games, or Pogo, you need to have Shockwave up to date too.
I recommend a "full clean install":
Download the following by right clicking and selecting wither "save target as" (IE) or "Save Link As" (Firefox):
Note: The following isn't a download, It's a link you'll NEED TO visit with IE to get to the Shockwave Player 12 FULL Intsaller (ActiveX for IE)
Save five above files to your Downloads folder. DON'T run anything yet.
Reboot your system completely.
BEFORE opening anything else, go to your Downloads folder and run the Uninstallers.
Go to: C/Windows/System32 and delete the Macromed folder.
Go to: C/Windows/SysWOW64 and delete the Macromed folder.
Open your Registry Editor (Start>Run or press the Windows key + R and type "regedit" [minus the quotes] then click OK).
In the Registry Editor, go to: HKEY_LOCAL_MACHINE/SOFTWARE and delete the Macromedia folder.
Goto: HKEY_CURRENT_USER/Software and delete the other Macromedia folder.
Close the Registry Editor and empty your Recycle BIn.
Run the Flash Player ActiveX installer, the Flash Player (other browsers) installer, and the Shockwave FULL installer downloaded previously.
Then open IE and visit the above link to install the ActiveX FULL shockwave plugin. (Note: it says "11" but it's 12)
You've no doubt noticed I mentioned NOTHING about Chrome in all of this.
That's because Chrome uses its own "proprietary" build of Flash Player, and you CAN'T update or reinstall it here.
Thanks, but I've a couple flies in the ointment.
In the link you provided to install ActiveX FULL shockwave plugin for IE, I gather that I'm to go partway down the page to Install Shockwave Player on a 64-bit Windows operating system. Problem is that this laptop only seems to have a workable 64 bit version of IE. When I open Program Files (X86) and open the Internet Explorer folder, clicking on iexplore,does nothing. However I don't really care, since youtubes play on IE.
And since I've already done all of your steps up to the IE SW plugin, I assumed that youtubes would now play in Firefox.
They don't. I still get the error box about Shockwave not responding, cancel or continue, and continuing still gives me 'An error occurred. Please try again later'
And what do I do about Chrome? That actually is the default browser on the laptop. All I get there is 'An error occurred...',same as Firefox msg.
Resetting Firefox did nothing. I used Revo Uninstaller to remove Chrome, now I can't reinstall it because it says it needs some Windows Updates before Chrome can be installed, and I can't acces the Windows Updaye page - it just sits there when I go through Start/All Programs/Windows Updates....
One important Update and 1 optional. A Net Framework 4.5.1 update (important) failed with an unknown error - 00000001 and although IE10 installed correctly, it was unusable both in 64 and 32 bit. Unfortunately uninstalling IE10 and going back to IE9 did nothing, so at this point even IE9 is useless, so I've now lost Chrome and IE. .
Sounds like you've got some serious OS issues.
Have you run a System File Check (SFC)?
Start>Run (or press the Windows key + R) and type "sfc /scannow" (minus the quotes and with a space between sfc and the /)
It'll check all of your system files and repair what needs it.
sfc /scannow found no integrity violations. Startup Repair (accessed through F8) found no problems. Chkdsk /r /f detected no problems.