**UPDATE Dec 14, 2012**
As pointed out by Carlos below, the easy way is to simply delete the wireless profile. Run this from an elevated command prompt:
netsh wlan delete profile "SSID-name"
I was playing with my wifi AP and turned SSID broadcast off. Of course, several wireless machines on my network wouldn’t connect because they weren’t configured to connect if the SSID wasn’t broadcast. They all were an easy fix, except for my Windows 8 test laptop.