Log-on screen

How do I get rid of the network of windows log-on screen? I do not want these log-on screens to prompt me for passwords because I do not enter the password anyway, I just cancel it. In a PC with LAN Card installed (NIC) and is connected to the internet via cable modem, theres really no need to log-on. So how do I get rid to these log-on screen, both for network and windows log-on?