I agree Troelsen's book is very good BUT as a former instructor NOTHING beats a textbook with structured lessons. Deitel and Deitel are arguably the best textbook publishers and "C# A Programmer's Introduction" is what I would recommend to get started from scratch. Expensive but worth it if you are disciplined enough to do every excercise as if you were in school else a waste of money that will end up on the shelf next to Troelsen's "C# and the .NET Platform."
Clinton Gallagher