I run it in a PII 400 mhz with 386 mb of ram. Its slow but for now I cannot upgrade my computer. Hope to do it in a month or so. I wouldn't run in in Win 95, 98 or Me. I run it in Windows 2000. I'd say if you run it in a low end machine like mine, you need an OS that has a more robust memory management like Win 2000 or XP.