If you want to play with Linux, I've found one of the easiest to install and has similarity to Windows is Linux Mint. If your hardware is old, there's a 'light' version of Linux Mint. You can also try before you commit to it by creating a bootable Linux Mint USB using a Windows app called 'Rufus'. Yet another option - buy a new hard drive and use the bootable Linux Mint USB to install it to the new hard drive. Keep your Windows drive hooked up in the computer, and you will be able to browse the old drive.