How can I create a subkey in the registry that contains the installation directory. I am using the setup project that comes with Visual Studio .NET to install my program.

Thanks in advance.

You can create it on loading your 1st form :-

objRegKey = Registry.LocalMachine.OpenSubKey("<yourregistrypat h>", True)
objRegKey.SetValue("AppPath", Application.StartupPath)
objRegKey.Close()

OR

you can do this via the registry editor from the setup project :-

right click your setup project click view then select registry. From the left window select where you want the key to go.
From the right window right click -> new -> string value