Some sites using Java and/or Flash seem to work better in one browser than in another. If you're using Internet Explorer, try switching to Firefox:
http://www.mozilla.com/en-US/
(Alternatively, switch back from Firefox to IE, to see if the site will load properly in that).
To check whether Java is enabled under IE, go to Tools > Internet Options > Advanced and check that there's a tick alongside "Use JRE . . .".
To see if Java is enabled in Firefox, go to Tools > Options > Content and ensure that there's a tick alongside 'Enable Java'.
Chris