Code lines in VisualC(or VB) that add a new menu in Excell's menu bar

[Lost User]

I want to know if it's possible to add a new menu in Excell or Word running an external program(in VC or VB) without using the Customize tool in Excell(or Word). If it's possible give me some code lines or some basic concepts or some web pages where a can find a way to solve my problem.