Is it possible to utilize the sendInput function on windows that currently do not have focus, and maybe through the use of multithreading, sendinput to multiple minimized wi
That is not possible with SendInput. What you probably want to do is find the messages that were sent to the window by the OS when that particular event was performed then emulate them. You can use Spy++ to attach to the target window and perform your event. Then use SendMessage() and PostMessage() to reproduce the messages that were generated by your event. This will work fine for notepad.
If you do use this method, note that you need to send messages to notepad's child window which you can find with FindWindowEx() with a classname of "edit". For example to type text you could try WM_KEYDOWN. You should note that this method is not necessarily reliable: http://blogs.msdn.com/b/oldnewthing/archive/2005/05/30/423202.aspx