Thanks for the replies thus far. I'm running IE 7. I thought it might be a security setting or plug-in, but I'm not sure which. The only video or audio format my IE will launch (embedded or external) are Quick Time extensions. Otherwise, clicking on a link that contains video or audio results in the error message "Internet Explorer cannot display this web page." The strange thing is that a fresh install of Windows and IE on a new PC doesn't have this issue either, and new installs wouldn't have any plug-ins installed either. My laptop worked fine from brand new, and machines I've built for other people work fine immediately after the install. I know it's something simple, but I can't figure it out. Could it be McAfee?