hard drive appears blank with external enclosure kit

First, I’m no tech (as you’ll probably notice from this post).
Anyhow, our Toshiba laptop died — problem with XP. It wouldn’t boot up due to a problem with system32 or something like that. So, following the directions given for data retrieval elsewhere on this site, I bought an USB external hard drive enclosure. It’s all set up and plugged in, but it appears to be completely empty.
How do I find my files? Is it possible I erased them somehow between removing the HD from the laptop and plugging it into the external enclosure?
Help! There are ~3 months of pictures of my son that I had not uploaded to our online storage that I’d really like to have.