Calling all nerds! I can't watch videos on youtube or myspace anymore? Please help me!?

The error message reads 'Hello, you either have JavaScript turned off or an old version of Macromedia's Flash Player. Click here to get the latest flash player.'

I have tried the following:

- Uninstalling and reinstalling my Flash

- Uninstalling and reinstalling my Shockwave

- Uninstalling and reinstalling Java

- Making sure my javascript is turned on by customising my security settings

- Using Mozilla Firefox instead of Internet Explorer

The weird thing about it, is that if the video is on a third party website, such as Bebo but its a youtube video I can watch it. Or if its on the youtube homepage already loaded up, I can watch it. But when I click into a video it doesnt work, I get the above error message instead. Im at a total loss as to why this is happening because this was never a problem before. I'm just about ready to kill somebody so PLEASE help if you can. Any answers would be appreciated. Thanks guys.