By old I meant the design of the card. The card was designed a few generations back from current cards. Even my newer 6600 TD is technically obsolete since the 7000 series came out :) They still sell the card online and at several stores, but the technology is fairly old and lacks a lot of the built in functions newer cards have. If you go to the NVidia site, you can compare the differences. I mentioned the odd hangs and issues I have had with Carrara as an example of some of the weird things which can affect the program that you would never think would. I generally stick with XP mainly because it has almost the same core kernel as 2K but also has more optomization for other non business apps like games etc. I also prefer the interface since after working maintaining w2k servers until I was disabled a few years ago; I really never want to see 2Ks interface again... argh.... I'm just waiting for Vista to come out so I can finally take full advantage of the 64Bit dual core Athlon I just got. I am currently having a particular issue with C5 as well. Mostly I think I may have overdetailed a scene I am doing, including three poser characters I imported. I get the Unknown error as well as memory allocation errors. I actually had to reinstall C5 just to get it to load the file. As far as getting to Render it, I am going to have to turn off all my indirect lighting. :( Well good luck with the issue, keep us posted.