Rendering HD video in a video editing suite is a very resource hungry process which requires a lot of free RAM. The chances are the program is freezing due to a lack of RAM in your PC. I'm afraid fixing that necessarily gets a bit technical. I am not familiar with that particular editing suite but some or all of the following may be relevant.
1. You could do a clean up on the PC or laptop you are using to ensure it is capable of operating at its best. Especially look at start up program and programs that run in background. They will all use RAM. In any case make sure all other programs are closed down when rendering
2. Some editing suites have a settings or set up that defines the amount of RAM made available. You could alter that setting. Allowing it to access a high percentage of your available RAM may sound the sensible thing to do...wrong. The PC/laptop also needs RAM to run the OS and other systems so giving the application too much access can stop the PC/Laptop operating. If there is such a set up, there should also be advice on the best RAM setting.
3. If you are using a PC...does it have a decidated graphics card and is the editing suite enabled to use it. A dedicated graphics card has its own memory which means it does not have to share processor memory.
4. If you have the capability on your PC, load the editing suite on a different drive to the operating system, and preferably have your data store ( the drive where the rendered video is saved) also on a separate drive ( even an external one).
If all of that sounds too complex then some simpler steps might be to reduce the length ( and therefore total size) of video to be rendered and use lower bit rates and resolution/Framerate setting in the render template. So a lighter load on the PC/laptop would be render out at 720 resolution....25/30 frames per second........8mb bit rate. rather than 1080/25 ( 30) at 12mb.
Another method is to load intermediary files into your editing suite via Gopro studio...........these types of file are far easier for a Laptop/PC with limited processor power to manage.