OK, so the "upgrade" is really a downgrade so that's out of the window and the CD in the bin.
My choice is VB .Net, Java or C++. Many many moons ago (on my Sinclair Spectrum! ) I got a C compiler but couldn't make much sense of it.
In reality, I think I am more inclined to .Net because it's basic and it's what I'm most comfortable with. The leap from Sinclair, BBC, Pick Databasic and QuickBasic to VB was a difficult enough one for me.
The next question is, what is the difference between these 3 languages as far as the kinds of application that can be produced. For example, are they all capable of writing windows based apps that manipulate a database and format and display the results? That is the main thing I would be using it for since I am nothing more than a hobbyist.