Nadya,

>What exactly do you mean here? Also I don't want to change enable property of the page back and forth.

If they can't proceed from one page to another, then the other page should be enabled until the proceed criteria is met. But that requires toggling Page.Enable. You've not really said what you are trying to accomplish with your deactivate code or why it can't be called when the same page is clicked, so it's hard to recommend other possible solutions.