How to get my program to log the user into Windows?

i have been working on a program that will enter usernames and passwords if someone plugs in a Usb, but i don't know how to enter a 开发者_如何转开发windows log in password. So the idea is to have my program running so it can find if the usb is plugged in if so it will use keybd_event to enter the password and to hit enter. how would i get my program to run so i can do this?

You need to write a GINA DLL (XP) or a Credential Provider (Vista / Seven)