PID to HWND

Well, I see this has been asked several times over the years ... I want to run Winows 8 File Explorer (I have the PID) and set the size of the window (I need HWND).

I tried (http://www.autoitscript.com/wiki/FAQ#How_can_I_get_a_window_handle_when_all_I_have_is_a_PID.3F). It works for Notepad.exe but hanges up for Explorer.exe. I don't know how to use (http://www.autoitscript.com/wiki/Snippets_%28_AutoIt_%29#WinGetHandleByPID).

Thanks!