Because PSU is from 2006, it runs on almost any modern PC. However, you will likely need: (legacy components) enabled in Windows.

It is entirely free, as these projects are fan-run and cannot legally charge for SEGA’s intellectual property. 3. PSU-Classic & Offline Mode

The retail version of PSU is "abandonware." While you can find physical copies or ISO files online, they won't work for online play without a fan-run server. SEGA no longer supports or distributes the game. 2. Clementine (The Private Server)

Other smaller projects occasionally pop up to preserve specific versions of the game (like the Japanese "AOTI" expansion). 4. Technical Requirements