HELP, RAM FULL

hi, I have a Dell G3 15 with 16gb of ram. Lately I have been working on editing a video with the Vegas Pro 18.0 program correctly installed and often the program crashes. Particularly amazed, I went to check the performance of the pc, and the RAM is at more than 80% even without the active program. I restarted the pc but the values ​​do not go down and no open applications are detected that can occupy 16 GB of ram. I have to work on this video, but it is a great difficulty. Do you know what I can do? I thank you infinitely.