You didn't accidentally uninstall your NIC driver, did you? It's been a while since I went through troubleshooting network issues, so maybe I'm forgetting a simple step or two, but this is the direction I would go if my wi-fi stopped working.
It could be a few things that are hopefully easily correctable.
1) If you're on a laptop, some have a button that turns your wifi on/off. Make sure that it wasn't accidentally turned off. Also, on the task bar, by the clock, hopefully there's an icon indicating that you're not connected to the network. You can click on that to see if you can locate your network and then reconnect to it. If by some chance these don't fix your issue.....try restarting your computer again for good measures.
2) Make...