Continuous crashing

So I've been editing a movie I made and after editing 3/4 of the movie (now about 1 hr 13 minutes of content done) Premiere Pro CC 2017 slows down to an unworkable state and then crashes. I've tried clearing the cache in appdata/roaming/Adobe/common. That didn't work. I've checked to see how much of my CPU and RAM is being used when the program is running: CPU at 30% and RAM at 60%. So that shouldn't be the problem either, right?

I've used Premiere to edit files this large in the past (on the same PC) and never had any problems like this. But this is the first time I've used Premiere Pro (and hence this version) in about a year. So I'm wondering whether this version of the product isn't simply buggy and whether I shouldn't just ask for my money back and try different software.

CPU: i5-6600k

RAM: 16 Gb

OS: Windows 10