I have a disk for Photoshop Elements 4.0 marked Windows XP. My computer is running Windows 8.1. Will the program I have run properly, or do I need to upgrade it? If so, how much will it cost me to upgrade it?

As I said, I have a CD which is marked Photoshop Elements 4.0, Windows XP.  My operating system is Windows 8.1,  Will the program on the CD run properly?  If not, who will it take to upgrade it?  drydene@earthlink.net