This is an HP 3500 Pro. It has an I5-3470 CPU with Intel HD Graphics 2500 built into the processor itself. This hardware acceleration facilitates video decoding making these boxes an excellent choice for Kodi, Plex servers, or home security cameras. It has 8GB of DDR3 RAM, a 500GB HDD, plus a 1TB HDD for secondary storage.
I have installed Zorin OS (Linux based) and it looks and feels like Windows. It comes with the LibreOffice suite which means you don't have to pay for Microsoft 365. It has a software store where you can install lots and lots of other open source apps like Kodi, Plex, Jellyfin, VLC, even Google Earth. You can also play some of the retro games, like Wolfenstein and SuperTuxKart. The version of Zorin OS that I've installed is the Educational version, so there are a great many STEM programs in case you've got someone who is still in school. The software has an automatic update feature as well to keep your OS secure and up-to-date.
I have a few of these, and I can even set up one with Windows 10 if you prefer. A brand new mouse and keyboard from HP are included with each PC. Be aware that there are not any HDMI ports or DisplayPorts, so you'll need cabling to work with either VGA or DVI connections at the PC end. Monitors are not provided.