Nard,

   You cannot play the files through any program except Security Server.  Please do not browse to the files through My Computer.

   Inside of the server, you can click the playback mode, and browse for video recordings.

If you are only getting recording from 1 camera, then please check your Schedule settings to ensure that you have configured it to record from both cameras.

Thank you 
Platinum CCTV Support
http://Platinum-CCTV.com