Recycling your code or existing classes is not a prerogative of .NET. Any programming language allows you to do the same.
I think you misunderstood there Esposito, what Gary was saying is that the .Net Framework provides a large number of inbuilt functions that can simplify and greatly reduce the amount of code you have to write.

I know that for instance one of the first programmes i converted from VB to VB.Net was greatly reduced in the lines of code i used to achieve the same result.

Once you get used to the .Net language(s) they can really speed up your development.