Does your router have a connection log? Are you able to specify a static IP then?
I once had a problem where android devices wouldn't connect to the wifi, I enabled the guest account on my Wifi so it was broadcasting two SSID's and suddenly they'd start connecting.
Is this true of all wi-fi you've tried to connect to? Or just your own?
What router is it? If it's one with a dual WPA/WPA2 encryption, then set it WPA2-AES only. Should work fine. If it's a BT Homehub, then have a bug where a wireless devices gets blacklisted for no reason, only way out is a factory restore of the router itself.
http://bt.custhelp.com/app/answers/...reset-my-bt-home-hub-to-its-factory-settings?
Don't forget to set your wireless to WPA2-AES when done, saves you a lot of hassle in the long term - use exactly the same wireless key too.
try putting it into airplane mode? you could always send it to Samsung.