Thanks for the replies everyone.

I've installed various plugins for it but still no luck.

I loved being able to see what the music was like before buying it as I buy quite a lot of my music online but now I won't be able to do that. Is there ANYONE who can help me?! I've gone to the help centre on the Sibelius website but they were no help whatsoever so I'm at a loss as to what to do. It worked OK on my old laptop so I don't know if it doesn't work properly on Macs but it says it does so there must be something I can do to fix it. I use Firefox but it's a little different to what it was like on my PC as I'm using Mac OS X instead of Windows.
If there's anyone that knows how to cure this problem then I'd be really grateful if you could let me know.

Thanks again,
Lisa xxx