Looks like something has gone wrong without your installation somewhere.
The easiest way to fix it may be to just bite the bullet and do a complete un-install - re-install, unfortunately. You could also have a search through these forums for installation issues, there is a sticky at the top of the forums here about installation most people's problems have been solved.
Before you do that though, you said that you re-installed, not un-installed and installed again Visual Studio and DarkGDK. If you arent aware, you also require the DirectX SDK August 2007 version, and the order that you install them in really matters, as it wont work if you dont install things in the correct order.
Once you have everything, Visual Studio, DX SDK and GDK un-installed the order to re-install them is : (if you already know, just disregard

)
(It's best to let the installers install to their default locations as otherwise some things wont be setup correctly, like project wizards)
- Install Visual Studio 2008 C++ Express Edition
- Run Visual Studio 2008 C++ Express Edition once(this is very important, it needs to be run once before you install anything else as it has to setup a bunch of environment variables for the following installers to use)
- Install DirectX SDK August 2007 version
- Install DarkGDK
Once its installed in the above order, you can fire up Visual Studio and you should be able to start a new project, select Wizards when it asks you project type and in the following pane you should see 3 DarkGDK project types.
If it ain't broke.... DONT FIX IT !!!