If the power goes off to your router, all the little knobs and buttons are likely to reset. In such cases, wire works but wireless doesn't.
Open up the router by typing 192.168.2.1 on your browser. I don't use a password on my router. Check all the little things you can look at and make sure they look right. Go to the tab or button that says, "clients" and see how many clients there are. If you have a working computer wired to the router, you should see at least one client.
When troubleshooting wireless problems, always turn off the WEP or WAP key until you can see your laptop on the client list.
With your key turned off, if your laptop won't connect, make sure the network switch is turned on and also try to make sure your laptop will connect to some unsecured (or secured) network, possibly a friend's.
If it still doesn't work, go back to the router and pull the power plug. Leave it unplugged for at least two minutes. This will reset the router to defaults, however, your wired system will still work. Enter the router and make sure it is set to work with wireless by typing 126.96.36.199 on your browser.
Most virus checkers will block wireless, so if all else fails, turn off the firewall. If the laptop connects, you will have to consult the AV guys for a fix.
If none of the preceding hints and these hints don't work, you will need to have someone go inside your laptop and check the settings, particularly that the proper protocols are installed and that the wireless receiver is turned on at the system level. Any computer savvy kid can do this.