To lock focus on a form in Delphi 7, enabling it to behave like a MessageBox, the implementation involves creating a boolean variable to manage focus retention. The example code defines a form with a method that sets the boolean based on a condition when a button is clicked. Additionally, an OnDeactivate event handler checks the boolean; if the condition to release focus is not met, it beeps and retrieves focus back to the form. Discussions also highlight a perceived decline in Delphi's popularity, suggesting users seek help in more specialized forums rather than general ones.