In a Windows VB.net application, how do I write a code that will give me a particular App's folder location?

I didn't understand what is "App's folder location", but you mention Registry, so here is a code snippet in VB.NET that summarizes how to work with Windows Registry:

Imports System

Imports Microsoft.Win32

Module Module1

Sub Main()

' Create a new key under HKEY_LOCAL_MACHINE\Software as MCBInc

Dim key As RegistryKey = Registry.LocalMachine.OpenSubKey("Software", True)

' Add one more sub key

Dim newkey As RegistryKey = key.CreateSubKey("MCBInc")

' Set value of sub key

newkey.SetValue("MCBInc", "NET Developer")

' Retrieve data from other part of the registry

' find out your processor

Dim pRegKey As RegistryKey = Registry.LocalMachine

pRegKey = pRegKey.OpenSubKey

("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0")

Dim val As Object = pRegKey.GetValue("VendorIdentifier")

Console.WriteLine("The central processor of this machine is:" + val)

' Delete the key value

Dim delKey As RegistryKey = Registry.LocalMachine.OpenSubKey("Software", True)

delKey.DeleteSubKey("MCBInc")

End Sub

End Module

More sources below.

Hope this helps ...