I using windows vista 32 and browser is chrome until about january 7 2014 was working fine then must have updated or something now videos will not work!! originally youtube didn't work either but fixed that by changing to https:// rather than http://. I have version 12 latest update now computer says its installed but any other thing that uses flash either tells me to update or comes up with blank screen i have tried nearly everything and from uninstalling nearly 5 times now, different browsers including ie and firefox neither work!!! and man things that iv wanted to download have been unable to due to running off flash and i cant see the download button or if it is there doesnt work.
OS: windows vista 32
browser: chrome latest
flash version the latest
https = a secure site (like when you're logged into an account at Amazon - notice the padlock)
http = a non secure site (like when you're at amazon but NOT logged in - no padlock)
YouTube ISN'T a secure site, even when you're logged into a YouTube account... UNLESS you're viewing PAID content.
If you needed to change to https to get videos to work, I'd venture a guess that something in your firewall or anti-virus settings was changed and required you be on a secure connection for plugins to work.