External processes in VB.NET

Hello Im new here so I might as well begin my queries. This is one of the best forums ive been so far concerning C# and VB.NET. Im just wondering how can you call externel EXE files and run them in your WindowApp in VB.NET; say you want to launch notepad.exe or MS Word when you click a button in your Windows Form. Thanx and more power to this forum.