Can't connect to WiFi

After updating to 2.2.1 I cannot connect to wifi. In fact, it will not even detect any wifi to connect to. I have even tried to enter the name of the network. I've restored everything, I've reset everything, I'm at wit's end!!! Please someone post some new ideas. I have done everything possible and still cannot get it to work. I can pick up E and 3G networks, but no wifi!!!!

Just a thought but is your wifi switched on???