Notes 8 isn't officially supported on Windows 2000, but I know from first hand experience that the Basic edition works. That got me to wondering how far back you could go. I got it installed on Windows 95 B (which wasn't easy), but it won't load:
SetProcessAffinityMask is only available in versions of kernel32.dll that started shipping with Windows 2000. On a lark I tried copying that file to Windows 95, but then Windows wouldn't load. It looks like Windows 2000 is as far back as you can go and still run Notes 8 Basic without getting into hacking DLL files.
I knew you were curious about that. :-)