windows service, login - on-event application ;)

Hi,
need some help with application which should work like that:
when you turn on computer you see windows login screen, to the computer is connected smartcard reader, when you put the card it checks it. When it is ok windows login on a specific user.

or alternative version:
you login as a user, application in c# opens adn blocks mouse and keybord (fullscreen application i think. It asks user for a smart card and after checking it it unblocks computer.


if anybody have an idea how to make it (some code examples, maybe articles) I would really appriciate it