Watermarking a compiled exe program

Hi, we are looking to watermark an executable program. Sadly, we do not have the source codes so we have to do it the unorthodox way. The watermarks should only appear when the user is at the main page of the software, and disappears when the user navigates to other areas, then reappears if the user were to navigate back to the main page. We already have a working prototype for this watermarking software using a combination of AutoHotkey and Screen Watermark software on sourceforge. Basically the program has 2 parts: Part 1 - Loading Watermark 1. Loading watermark image appears 2. Run compiled exe software program 3. Remove loading watermark image upon successful load of exe 4. Run Part 2 ** The detection of successful load is currently done using pixelgetcolor function in AutoHotKey to detect a change in color of a pixel that signify the software is loaded. Part 2 - Main Page Watermark 1. Check if user is at the main page 2. Add watermarks if user is at the main page 3. Remove watermarks if user is not at the main page 4. Loop steps 1-3 as fast as possible Right now what we have achieved using AutoHotKey is not fast enough. There is still a significant delay of up to 500ms before the watermarks appear. So that why we need your help!