I'm a computer guy, but pc's aren't my forte. I would start by deleting cookies/temp files, restart browser. If that doesn't work, you may want to ensure that you have the latest version of Flash player. Upgrading it may fix problem. You could also try another browser; Firefox is working fine for me.
Edit: if you are trying to watch from work, you may be blocked by their software, websense or something of the sort.
Aaron
Edit: if you are trying to watch from work, you may be blocked by their software, websense or something of the sort.
Aaron