Difference between Private Sub, Function and Class

What are the differences between the following:

• Private Sub
• Private Function
• Private Class

When should each one be used?

Private is a modifier than gives the scope of the class, sub, or function.

A sub and a function are both subroutines, or sections of code that can be called in the program. The difference between them is that a function has a return value and a sub does not.

A class is a group of codes that can include subs, functions, and other stuff.

Sub is like a function but it doesnt returns any values it just executes a proccess

Class is a Class, Sub and Function are methods, private is an access modifier

now check this link,

http://msdn.microsoft.com/en-us/library/ms973814.aspx