Okay, it's time to get down to it. Is your wireless network running slowly? Do you have intermittent losses in Internet access and you can't figure out why? First, take a breath. In all likelihood, no one is stealing your Internet. Tons of things could cause a slow connection. Your Internet service provider might be having issues or is overloaded with traffic. Your WiFi router might be experiencing interference from other electronics, or simply be having trouble penetrating the walls and furniture of your home to get a wireless signal to your computer.
There's only one thing you need to prevent 99.9 percent of wireless squatters from using your Internet connection: a password.
The most basic element of wireless security is an encryption protocol such as WPA2, or WiFi Protected Access. Older standards like WEP and the first generation of WPA have been phased out for the more secure WPA2. You don't need to know anything about how the encryption works -- you just need to set up WPA2 security on you wireless router and set a password for the network. Make it something you can remember that's not easy for others to guess (please don't use "password" or "12345!") and you'll be well on your way to security.
So how do you do all of that? Well, that varies by the type of router you have, but most WiFi routers are accessible from a connected device via the address http://192.168.1.1 in a Web browser. Logging in is usually easy, too, as most router manufacturers use a simple pair of words like "root" and "admin" for the device's login and password (you should be able to find this information in the manual). That will take you to a management tool where you can change all kinds of settings, including your wireless security.
That tip might set off a little security alert in the back of your head. "Wait, a minute," you think. "If most routers use the same local address and login/password, couldn't anyone get in there and mess with my security settings?" Well ... yes! Without a password, your wireless network is open for anyone to hop on. But a password isn't quite all you need to be totally secure. You should also change the router's login information to something aside from the usual "admin." That will keep virtually everyone from messing with your router -- but let's take a look at how to detect a WiFi leach, just in case.