I have a Dell 780 dual core 3ghz with 4gb ram.  I have Moviemaker 2012.  I have created a very large & time consuming project involving over a thousand video & image clips. It is about 2 hours in length and about 7gb in size.  I have saved/published the project to HD 1920x1080 MPEG-4/H264 format, and it appeared to have been successful, but when attempted playback on VLC, it would not work, just a black screen.  It would not play on WMP as well.    I have updated the latest driver to my graphics/display card, and I have all the latest video codecs that are available installed on my computer.  I intend to divide my project into two halves, (to reduce the project size), publish both halves, then reconnect them with a video editor. To do this I would have to delete one half of the project, then save it, and vice versa.  Rather than delete each video clip singularly, is there a faster way to batch remove/delete these clips?  I would appreciate any further advice what to do in this situation.  Thank you.