System.Diagno
What you want is pipe the output of the exe to your process. Usually when you do not do not pipe the output it defaults to stdout for a console application will be the console window by piping you are telling the exe you want the output to come to your process not the console window. Then you would have to create your own "panel" (a multiline textbox) and append the the output stream from the exe you invoked to it!
Learn here: http://msdn.microsoft.com/en-us/library/system.diagnostics.processstartinfo.redirectstandardoutput(v=VS.90).aspx
I think what you are talking about is embedding an application in your panel.
This is only possibly with executables that have been created to be embedded. Notepad is not one of those. Some browsers can be - Mozilla is one example, and IE is another.
I guess you are looking for this: Window Tabifier
What are you trying to do? you know that if its your own programs you want to run in the panel you could write some basic plugin code and get a control from a assembly with reflection..