You can connect your laptop to the Internet or a local network through a wired LAN, a wireless Wi-Fi connection, a dial-up Internet service or a mobile-telephone company's wireless data service. Each type of connection requires a different kind of network interface adapter, and an account with a different service provider.
A laptop can establish a wired connection to the Internet through its Ethernet port (or a separate network interface adapter), or through a modem to a telephone line. Wireless connections can use a Wi-Fi access point, or a wireless data service; many laptops have built-in Wi-Fi radio transceivers, but each cellular data service requires a separate adapter that plugs into the computer's PC Card socket.
Regardless of the technology you use to connect, Windows can create a Network Connection profile that sets up your access to the Internet. Many laptops come with network management utilities that can allow you to select the profile you want to use for each session; if yours doesn't include one of these programs, several commercial programs can perform similar actions for you.