HotkeyNet can send keystrokes to two AOC's on the same computer, but only if it keeps changing the focus (bringing the two windows alternately to the foreground). It does that automatically but it's a nuisance because it causes a delay, interrupts movement keys in the foreground window, etc. The reason I suggested locking one of the windows on top was because I thought that might make focus switch faster. Focus switching seems to happen faster on faster video cards so it might be barely noticeable, depending on your system.