Entire Timeline won't Render in Elements 15

I don't know for sure, but I think it was the size of my clips.  Imagine a 6.2 gig two hour clip that you have in your project media.  It's an MPEG-4 huge clip. I was taking that clip multiple times down to the timeline, then shrinking it for individual shots.  I was thinking it would reduce the file size in the timeline, which it wasn't.  So I was having a dozen or more 6.2 gig clips.

I got new program called Bandicut.  It allows me to put my huge MPEG-4 clips into the program, cut out invidual 2 and 3 second clips (or longer), then export them without re-encoding (lossless).  So now I have small 2 and 3 second clips around two megabyte size.  I will then put them in the project media and see if it works.

I did and it made no difference.  I was experimenting this morning by taking the 20 minute clip to the timeline, then trimming it to a 10 second segement using the in and out points.  I then checked properties of the 10 second clip, and it still says 6.2 gig.  So in reality, just by shortening a clip in Premiere Elements does not reduce it's file size.  When I hit the Render button, it just goes back to the start of the timeline and plays the video.  It renders nothing.

Is there a preferred secondary program which I can put these Mp4 segments into, and then create just the short 2 to 5 second clips I need, then load them into the Project Media file?  In other words, if I have a 6.2 gig clip that is 20 minutes, if I split that file in two, I would have two 3.1 gig files of 10 minutes each?  Or if I cut out everything but a 5 second clip, it may be only 150 mb?  Just trying to understand how this works.

I have a lot of old Hi8 and MiniDV footage I have transferred to  Bluray data discs via a professional deck.  It's a lot of footage I had to warehouse, especially the Hi8, before it went bad.  The Bluray segments can be 20 minutes or more and pretty large files.

I use handbrake to covert the Bluray footage to MPEG-4 and they easily go into Premiere Elements as clips in the media bin.  The shorter 5 minute clips seem to work ok, but imagine looking for 5 or 6 shots out of a 20 minute clip.  I pull it down onto the timeline at the far right, then scroll thru it to isolate the shot, drag it over to the prior edited shots.  Then to find another shot on that 20 minute clip, it's the same thing again.  I have no other way to isolate the needed clips out of that large segment,
I am thinking that even though I isolate 2-3 second clips out, the file size is still huge.  Maybe that is what is killing my playback?  

I have no other program right now to allow the selection of small clips of video from my Bluray data discs prior to bringing them into Premiere Elements.

I downloaded MediaInfo, but I don't know how to get it to provide the tree view of my project.