Hi Danny
The link you provided just sends me to a secure YouTube sign in Window, not direct to a video, it also appears not to be a link used on the Yamaha demo page.
Can you view this http://www.youtube.com/watch?v=yrY6B_zwigA&feature=player_embedded as this is the concert Piano demo?
If not, there may be a malicious program redirecting to somewhere other than the official site, so update your virus scanner and run a full scan,

Bill