Problems with the Linksys WRT54G v2.2 router

A while ago I updated my Firmware on the router to whatever was most current on the Linksys site, and everything worked fine while connected through the router to my PC. I began to have some lag issues in video games, so I reset my modem and when I went to plug everything back in I could not connect to the internet, so I had to connect directly to my computer from the modem, which is how I am able to get on the internet now.

Well, now that I have a laptop, I want to be able to get online with it all over the house or use it to multi-task. I just tried to update the firmware and reconnected the ethernet cable from the router to my PC and the ethernet cable from the modem to the back of the router and even after the firmware update I still cannot connect to the internet, or get wireless on my laptop.

Anyone had this problem and/or know how to fix it?

Help would be greatly appreciated. Thanks in advanced.