In most cases, the only way to set up your Wi-Fi network to prevent hackers from breaking WEP codes is by switching to a different network security protocol. WEP has security vulnerabilities that let hackers easily steal wireless passwords, often in as little as minutes. Newer wireless security protocols offer a much greater degree of protection.
WEP's main weakness lies in how it assigns network codes. Each of these codes is a randomly assigned string of numbers generated by the router. When someone attempts to crack your network password, she analyzes pieces of data, called "packets," that are constantly passing over your network at any given time. Once she has enough packets, a hacker can perform an attack on your network.
Most WEP attacks are some variants of "brute-force" attacks. These attacks, similar to figuring out a lock's combination by just trying every single possible one, are time consuming, but certain to succeed eventually.
WPA and WPA-PSK are newer forms of network security. Because these protocols use long, alpha-numeric strings of characters, they are much more difficult to crack. WPA also allows the user to set her own password, unlike WPA.
While WPA-PSK is not invulnerable to attack, particularly from time and resource consuming efforts called "dictionary" attacks that use a huge word list of common passwords, this method is much less vulnerable to hacking than WPA and earlier methods.