Breaking up large video clips into multiple small clips.

My family had a whole box full of 16mm movies on short reels.  About four years ago I spliced them all together on to four large reels in random order thinking I could easily put them into some kind of order after they were digitized.  I ended up with four video clips 12.6 GB in size that run for about an hour each.  Using Windows Movie Maker I was easily able to select out several short clips from the large clips and combine them into a 476 MB movie that ran for about 15 minutes.  I have been asked by family members to break the large files down into several more shorter movies. Unfortunately I am now using a Windows 7 64 bit OS.  I downloaded the current Movie Maker and am totally mystified because it is so different than what I used before.  Is it even possible to do what I need to do now? I made a couple of efforts, but could not get past the limit of splitting the file into only two parts.