Use the UIAutomation framework shipped with .NET from 3.5+ versions.
XP has bugs, nasty ones, so please stay on course with Vista, or Win 7.
[http://msdn.microsoft.com/en-us/library/ms747327.aspx]
Feel free to ask questions, as some of these requires heavy coding. However, Microsoft does not build solutions, only frameworks, and this is *intended* side effect of that paradigm.