Application appears off screen

AltSpace, M. Then move it.

If you feel comfortable going through the registry, here's a way to reset Notepad's window position:

1. Close Notepad

2. On the Registry editor, go to: Computer\HKEY_CURRENT_USER\Software\Microsoft\Notepad

3. Delete fSaveWindowPositions and/or iWindowPos*

On Windows 8.1, press (Win)+← (left arrow), and the document will appear on the left half of your screen.  Then drag the size a bit and it resets the window position.