Why isn't my Verizon router letting me use Wi-Fi on my iPod Touch anymore?

My mom installed the AVG security program and everything has changed since. My iPod touch recognizes the SSID and I type in the WEP address (that I have been using for the last two years) that's on the Verizon Wireless router on my iPod Touch and it says "Unable to join network". I have done absolutely everything I could. YES, I did try going to Setting>General>Reset>Reset Network Settings and still nothing works.