Hello Steven,
I run Windows XP Home and Pro with a couple of put together PC's. based on the Shuttle XPC with a Nvidia2 card. No problems.
The Nvidia has a detailed set of instructions for set up to run dual display. Its a really good card and equally as good as most stand alone cards costing a good deal more.
Just make sure you have downloaded their latest drivers to work with XP and Hoster.
www.nvidia.com
I have just bought a TFT monitor for KJ work and set it up and it ran the words for kareoke singing without any additional tinkering. My main monitor dispays the singer's list with the small screen inset.
As someone who always seems to spend a lot of time getting things right I was pleasantly surprised at the ease with which dual display can be set up.
Regards from across the pond
Garry