Both Windows Vista and Windows 7 have the option for multiple user accounts, and it shows you a user welcome screen after resuming session or a fresh bootup. But this login prompt might be annoying if you are the only one using that computer. So if you want to auto login into windows vista without a welcome screen and password prompt, just do these steps.
How To Auto Login Windows Vista without Welcome screen and login prompt
2)Type netplwiz and press enter.
3)You will see a window similar to the above.Now select the user you want to auto login by default.
4)Then uncheck the box “Users must enter a user name and password to use this computer” as shown below.
5)After clicking ok, a window will pop up asking for your password.Enter the password if you have set one, otherwise leave it blank.
Now you will be able to log in to windows vista or windows 7 without password and will never see that nasty welcome screen.