How to gain access to restricted files on an external hard drive?

I have a computer that crapped out on me a long time ago, it has irreplaceable pictures of my son on it from when he was a baby. I never had a way to retrieve them until I bought an empty external hard drive cage (USB) recently. So I put the HDD in the cage and it recognized it on my newest computer but says that I dont have permission or that its restricted. I tried right clicking, going to properties, and giving myself access under the security tab. None of it works! It so frustrating because they are right there and I cant get to them! How do I get to these pictures? Please help, thank you!