You might do a search on "Windows NT" to see any previous messages. I've seen messages from people running Windows ME and Windows XP having problems with Version 5 but not many from people running Windows 2000. Windows 2000 might be the optimum system. However, other people seem to run Poser 5 on XP with no problems at all. I didn't see anyone running Version 5.0 on NT though. It might be that the installer for Poser 5.0 might check the operating system and refuse to load on NT. You should check on that before getting Poser 5. Considering how many people have reported problems with the approved operating systems and Poser 5, you should really scope it out before getting it for an unapproved operating system. If Curious Labs offered a demo, you could load that and run on NT but they don't. I think both 2000 and XP have program compatibility modes that allow you to run legacy programs under NT. There is never full compatibility. If you do go to a more recent operating system, you might consider getting another hard disk and setting up a dual boot system where you can boot under Windows NT and either Windows 2000 or XP. Boot under NT for your legacy systems. I did that for a while when I went from Windows NT to 2000.