Look at iOS Troubleshooting Wi-Fi networks and connections http://support.apple.com/kb/TS1398
iPad: Issues connecting to Wi-Fi networks http://support.apple.com/kb/ts3304
iOS: Recommended settings for Wi-Fi routers and access points http://support.apple.com/kb/HT4199
Additional things to try.
Try this first. Turn Off your iPad. Then turn Off (disconnect power cord) the wireless router & then back On. Now boot your iPad. Hopefully it will see the WiFi.
Go to Settings>Wi-Fi and turn Off. Then while at Settings>Wi-Fi, turn back On and chose a Network.
Change the channel on your wireless router. Instructions at http://macintoshhowto.com/advanced/how-to-get-a-good-range-on-your-wireless-netw ork.html
Another thing to try - Go into your router security settings and change from WEP to WPA with AES.
How to Quickly Fix iPad 3 Wi-Fi Reception Problems
If none of the above suggestions work, look at this link.
iPad Wi-Fi Problems: Comprehensive List of Fixes
Fix iPad Wifi Connection and Signal Issues http://www.youtube.com/watch?v=uwWtIG5jUxE
Unable to Connect After iOS Update - saw this solution on another post.
Note - When troubleshooting wifi connection problems, don't hold your iPad by hand. There have been a few reports that holding the iPad by hand, seems to attenuate the wifi signal.
If any of the above solutions work, please post back what solved your problem. It will help others with the same problem.
Is your network hidden? If you look through the forums you'll see some folks have had issues when the network was hidden and they went away once the network was un-hidden. I haven't tried it out myself, but I think that the iPad won't search for hidden networks.
If it is and you're doing it for security reasons you may want to consider not hiding it. The reason is that your other devices may be able to 'search' for the hidden network, but they'll also do it when you're out and about. So, the security issue is that your device would be broadcasting whenever you're out since it would keep looking for that hidden network connection. Anyone sniffing the wire would be able to pick this up and know you have a hidden network. Sorry, just my information security 2 cents added in.
Ha Ha. This is great. Here's another discussion on the forum, and the link goes into a lot greater detail around hidden networks. https://discussions.apple.com/message/18779369#18779369
Message was edited by: bedardjr8
I have the same problem currently but with my IPOD Touch nothing is working with it I have looked at all the articles and reset the network settings. But when I go to my wi-fi nothing shows up under choose a network it just keeps searching and it isn'ta hidden network either. When i type in my network and ask to join it comes up with a message saying: could not scan for wireless networks. so idk what to do on this anymore. My ipod is also running on 5.1.1