Cause of the Problem:
The Problem could be due to several possible scenario's. Either the browser is stuck, or the you clicked on the screen during a QuickTime video, causing it to pause.

Solution:

• Check if the browser is stuck:
  Can you minimize the browser window, or open one of the menus? If the browser does not respond, it is stuck, click here.
  
  
• For QuickTime video:
  Did you happen to click with your mouse on the area in which the video was displayed?
  If so, this caused the QuickTime video to pause, click on it again to continue viewing the clip.