Hi Jack,
You need to use calls to the Minimize, Maximize and SetFocus methods of the application's window, but not of the application's process (it does not have such methods).
As for Internet Explorer, you need to find the child of the "iexplore" process whose WndClass property's value is equal to "IEFrame" and use a call to its Minimize, Maximize and SetFocus methods. For additional information, see the "IEFrame Method" article. Also, here is an example for Internet Explorer 8:
...
Sys.Process("iexplore").IEFrame(0).Minimize
...
