Saving iMovie Images

I have an old computer that doesn't work anymore. It still turns on and functions, it just is very slow and I cannot get anything done on it. I am a photographer, and I would like to save my videos from that computer and put them on this computer. The videos were not saved onto the photos app, they were only saved onto iMovie. I would like to take those videos out and save them so I can put them on a flash drive and switch them over to my new computer. How do I get those videos out of iMovie???