are you using DSL or cable?
Call the provider who sells you internet and try phone tech support, ask them to send a tech to get the thing fixed, OR with the computer running unplug the power from the DSL/Cable modem, wait 15 seconds, plug the modem back in, wait about 1 minute until the lights on the modem start blinking. Now restart the computer...
Unplug the router from power, wait 15 seconds, plug the router back in, wait 60 seconds, restart the computer.
Click on the internet/wireless icon in the lower right hand of your screen. Do you see a list of available networks? Do you know which network you want to connect to? Did you click on the network that you want to connect to?
Look on the router, is there a reset button? hold the reset button in for 15 seconds. This clears the security passwords.