HI..
I solved the issue by trashing the plug-in from the library, but of course I can't open the web pages that require it.
Not sure how that solved the problem...
Sounds like there may still be an old Flash version installed.
Follow the instructions for uninstaling the current copy of Flash then reinstalling here > Troubleshoot Flash Player | Mac OS
Then restart Safari.
From the Safari menu bar click Safari > Empty Cache
Try a video.
BTW... if you have the ClickToFlash extension installed, that can prevent Flash based video from streaming. It can also be installed as a plugin in /Library/Internet-Plug-Ins.
And check to see if Safari is running in 32 bit mode. Right or control click the Safari icon in your Applications folder then click Get Info. If the box next to: Open in 32 bit mode is selected, deselect, quit then relaunch Safari.
If you still have problems with sites that stream Flash content, from your Safari menu bar click Safari > Preferences > Extensions. If you have any installed, turn that OFF, quit then relaunch Safari to test.