want to login to windows progammatically
 

Hello all,

i want to login to windows programmatically,if some one had done such kind of thing please do help me.i have authenticate the user with LogonUser() funciton of win32 api and have also placed my application to windows logon by replacing logonui.exe in system32 folder.but i am unable to enter into windows.
I have seen winlogon theme which just replace the logonui.exe with their personal logon.exe but how they achieve the login process i cant understand and i dont think that they change msgina.So please do help me out.