EDIT it. Changing one thing will corrupt the exe permanently. The exe is binary code, but text document tries to convert some of it into readable text.
I did a test on that and you're wrong. If I open up the exe with a hex editor, I can change it then save it. Works good, actually.
Hex is just a different visualization of binary data, and so is ascii/unicode (text), but hex is meant to display numbers, and ascii is meant to display text. Every character is represented by a ascii/unicode number, but not all numbers are used, and unused characters are mapped to the empty square character. When you save your exe again, it messes up all the square characters, and thus corrupts the exe. Opening an exe in notepad is like trying to eat a steak with a spoon. What you're saying is that it does work because a knife and a fork can cut a steak in smaller bits.
