How to recast an ASPX application as Object Oriented
The object-oriented and procedural, or imperative, paradigms, and the functional, logical and mathematical, or declarative, paradigms are just that "paradigms." They are the embodiment of thought patterns and methods for modeling solutions. So long as the end result of a paradigm, the language used to implement it, is Turing complete, and the associated hardware can handle the needed elements, a solution that can be developed in one paradigm can usually be reproduced in another.

The issue shifts from "can it be done this way?" to "is this a satisfactory way to do it?" Some problems are better suited to one method while other are easier to solve using a different method. Using any paradigm to solve a problem, or implement a system, requires the ability to "think" within the model which the paradigm embodies.

I don't think it is fair to classify any practical solution as too simple, or too complex, for any given paradigm. Especially within the education arena, where the goal is learning how to employ the paradigm, and most "problems" are structured to meet educational objectives more than "real-world" problems.

As an "example" for future projects, the described system might even be too large for the students to apprehend while also trying to learn the basics it employs. If it had a smaller scale to it, the project could model several different paradigms in concert. Web applications are commonly developed using the MVC architectural pattern. The handling of the data (model of MVC) could be accomplished using a functional language, the HTML/JavaScript/CSS (the view of MVC) can be implemented well with procedural, non OO programming. The OO programming can be done in the system which gathers the data, and adjusts it according to the directives from the user.

However it's done, the hardest part will likely be converting something you know well, done in the paradigm you are most comfortable with, into something you don't have as much practice with, using a paradigm which is, for all practical purposes, a foreign concept. Having a bad example is likely worse than having no example. If you cannot "think" in OO style, you're unlikely to produce good OO code. Similarly, if you know VB.Net very well and don't know PHP very much, you can probably produce excellent examples of solutions in ASPX/VB.Net, and very poor examples in PHP. If you still want to reproduce your system using OO, or functional, programming, find a colleague who is proficient in the paradigm of choice to implement it for you.