Youtube problem, flash/java

[GooseHinson]

I'm currently using mozilla firefox and every time I try to watch a video in Youtube now (it worked 2 days ago), I get the message "Hello, you either have JavaScript turned off or an old version of Adobe's Flash Player. Get the latest Flash player." I have re-installed the flash player and have made sure java is turned on in my mozilla option. Youtube videos also don't work in my IE.

What's the problem and how do I fix it? Thanks guys.