No Video in viewer

The video codecs/demuxers on your system, or related registry settings, may have changed. This guide may help fix that:

Alternatively, disabling the Movie plugin will allow the Windows Media Player ActiveX control to be used, which may work better.

Alternatively to that, keeping the Movie plugin disabled and configuring the ActiveX + Preview + Office + Web plugin to enable the Windows Media Player preview handler (which is different to the ActiveX control) is another option. (If you are on Windows 10, you'll want to be on the recent big Windows update for that, since Microsoft broke their own WMP preview handler for about a year preceding the last update, which finally fixed it).