>Waht do users have to have on their machine to run .net apps? What's the best way to test for it?

You need the .Net runtime, which is a self-contained install.

To test for it you can check for hte existance of the Windows\Microsoft.NET directory, but you probably will also wnat to check the version in which case you can walk the folders in the Framework directory and pick the highest number.

Note that this makes sense only if you're doing something like COM interop from a non-.Net environment. I have some Fox routines that I use in Help Builder that check for the existance of .Net and they're written up as part of this article here:

http://www.west-wind.com/presentations/VfpDotNetInterop/DotNetFromVFP.asp

Look at the Installing .Net components section which deals with checking for .Net and then also registering a .NET COM component.

Hope this helps,

+++ Rick ---