Your System Specs Blow mine away... But I am running Windows 2k Prof and Poser 4.03 and am having no issues at all. I do however get an Out of memory error when I am trying to load a Poser Figure where I haven't gotten everything configured correctly (ie in the correct folders) but it isn't a critical error the model simply doesn't load, I fix the folders and then reload it fine... I run a PIII 800 with 512 MB Memory a GeForce2 MX with 32MB memory and a Dell 19 Inch Monitor. I am also running a PIII 400 with 128 MB of Memory and a 3DFX voodoo 4 with 32MB on a Generic 19 Inch monitor with Windows 2k as well. The only differences int he systems are the 800 I am running Win2k Prof with SP1 the 400 I am running Win2k Prof no SP. The 800 I am running Poser 4.03 the 400 I am running Poser 4 I run the 800 at 1600x1200 and 32Bit Color and the 400 at 1024x768 and 32bit color. I am sorry I couldn't help you with your problem other then to confirm that Poser 4 does in fact run on Windows 2000 Professional and it runs rather well.