Computer wireless networking help :)?

alright, it's christmas, and I'm trying to fix my mom's desktop. It's currently connected to a linksys wireless network (router's in the other room) but for some reason it won't connect to the internet. They tell me it hasn't worked since the power went off a few days ago. No other computer (there's like 5) has a problem. I've reset the router and modem, but still no internet. What am I doing wrong? or what could I try?