DWMX | ASP | SQL Sever 2000

I've developed an ASP page that is a simple questionnaire/registration form. The problem that I am having is that I want to ask a series of questions to qualify whether registration is necessary.

I would like to use an IF THEN statement to check the value of each question and at the end if all conditions are met change the hidden property on my form layer.

Can this be accomplished using field level validation or via a button click event?