There is no such thing as .Net 3.51. There is .Net 3.5 SP-1, is that what you are talking about?
Windows Vista was shipped with .Net 3.0, so it won't have .Net 3.5 Sp-1 inherently. However, Microsoft IS pushing .Net 3.5 SP-1 to any machine with any version of .Net on it via Windows Updates as a critical update, so more people have it than not.
You should check into the Client Framework and see if that will work for your application. This is a subset of .Net 3.5 that only includes the parts needed for a client application -- basically it's .Net w/o the web bits. I think it's about 20MB.
But I think if you use that, your clients will still need Internet access. How it works is if they don't have any version of .Net installed, it will install the Client Framework. If they have ANY version of the .Net Framework installed, it will try to go out to the internet and upgrade the user to .Net 3.5.
Can you use regular CD's instead of a miniCD? It seems like that would fix your problem.
RobinDotNet
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