SLide show with embeded video clip?

I am using Elements 12.1 on Widows 7.

I have created a still slide show into which I have embedded  a 14 second video clip in WMV format. Sadly the slide show runs until the video which starts but only for a short period perhaps 2 seconds then stops and awaits restarting by manual intervention which is of course not acceptable; what am I missing or can anyone suggest a solution? Thanks