Try this in Chrome. You don't have to keep Chrome but it does Flash natively so it can help diagnose this.
And let's be clear that ANY change is a change and can break stuff.
All of a sudden I'm unable to view videos, whereas I was able to just the other day. I haven't installed anything major that would cause such a change; I've also uninstalled then reinstalled my Flash Player, so I'm a bit puzzled as to why it's still not working. Any ideas/resolutions?
My computer is a Dell XPS 8300 running Windows 7 (64 bit) Home Premium with Service Pack 1. My default browser is Firefox 15.0.1.