CPU shuts down when I try to ddrescue from hiren's boot CD?

One of my hard drives are failing and I heard that ddrescue skips the bad sectors so that it can copy it into an image file but when I boot into Hiren's and run the command of ddrescue it works for a few minutes about 10 minutes then it just shuts down suddenly. I thought it may be a power supply problem but then when I boot with my healthy drives into my other OS it works fine and doesn't shut down by itself. Any ideas why it just randomly shuts down or how I can fix it? I really want to clone that drive since it has my files.