Thank you for your help guys. The problem is solved. Perhaps if I had provided more information I may have gotten there sooner.
Here is the story. My dashcam is a Blackvue DR650. The viewing software for the PC is good for viewing and has an option to import the clips (MP4 format) but only individually. I tried several video editors, including WMM, and I was unable to merge multiple clips into a single seamless video. Also, I gave GoPro a shot but it just froze on my computer.
Eventually I came across a dashcam viewer called Registrator Viewer. It's a freebie download and has most of the functions of the OEM viewer as well as the addition being able to select multiple clips then save them as a larger, seamless clip. This was my goal. Now I can go back to my default video editor and, in conjunction with Resitrator Viewer, carry on with my project.