Upgrade from .NET 2.0 to .NET 3.5 problems

I’m trying to upgrade our solution from VS2005 .NET 2.0 to VS2008 .NET 3.5. I converted the solution using VS2008 conversion wizard. All the projects (about 50) remained targeting to .NET Framework 2.0., moreover if I’m chan开发者_开发技巧ging target framework manually for one of the projects, all referenced dll (i.e. System, System.Core, System.Data, etc. are still pointing to Framework 2.0. The only way to completely change targeting framework I found is to remove these references and refer them again using proper version of framework. Doing it manually is not best choice I think. 50 projects ~ 10 references each ~ 0.5 minutes for changing each reference is about 5 hours to complete. Am I missing something? Are there any other ways of converting full solution from .NET 2.0 to .NET 3.5? Thank you.

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The .NET 3.5 framework doesn't include new versions of the base assemblies. System, System.Data etc are still version 2.0.0.0. Only the added assemblies have versions 3.0 (like WPF and WCF) or 3.5 (like System.Core and System.Linq). The runtime version (the CLR) is also still 2.0.50727

You don't have a problem.