Elements: Why do images edited one system look different on another?

I recently did a photo shoot with a black back drop, I have edited them on a Mac Book Pro, using photoshop elements the photo's look great and I printed them for the client they look good also. My problem is that I put the photos on a different computer, a HP laptop and the photo's looked terrible, you could see editing, creases in backdrop and the colour was different. Has this happened to anyone and what did you do?