Below is screen shot of C:\windows\system32\macromed\flash files @ today (my son tried downloading Adobe again today while I was at work, so all files are now dated 7 March) . However after each time we've tried downloading, the file "install.log" stayed dated 21/05/2010 and the FlashPlayer Trust sub-folder remained dated 6/09/2008 with a file in it called EACoreTrust.cfg dated 6/09/2008.
At suggestion of IT guy at work, used Google Chrome instead of IE9 to view YouTube and was able to view videos no problem! So if my laptop works using Window 7 and IE9, and my PC works using Vista and Google Chrome but not IE9, can I presume it is some bug or that I need some plug-in that enables the latest Adobe Flash version to work with both Vista and IE9? Would prefer to stick with IE9 if possible. From discussion with others on forums, it seems many are having the same problem, but even with Windows 7, and many also report having no problem viewing YouTube or other Flash sites using Google Chrome or Safari.
Just don't understand why this is suddenly happening when everything was problem free a few weeks ago - very frustrating, especially for my two boys who are cut off from their Minecraft and music videos! If it helps, I have also included screen shots of all the Windows Updates installed since 15 Feb 2013 in case you can see anything that might have caused a problem.
BTW, did you have any luck finding the info you were after about Flash Player versions in the YouTube video examples I gave you? I have tried several others since and can see no pattern or link as to what will play and what won't.
Image may be NSFW.
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Image may be NSFW.
Clik here to view.