I need to design a "Conditions of Use" dialog that is presented to users after they logon to Windows XP. It must not allow the user to proceed until they check an "I agree" box. It must not be possible to shut it using Task Manager or any other method. And it should be fullscreen and modal. The "I agree" will remain checked automatically during subsequent logins for the duration of 1 month, after which the user will need to check it again. Also HR want to track who has checked the checkbox.

Is such a thing possible using .Net? I can use C# to design it but I'm not sure about how to prevent users from bypassing the dialog. 

I know Windows Group Policy allows a dialog to be presented before login, but that does not allow a checkbox or any customization.

Any thoughts?