My Iphone will not connect to WIFI

My iphone has worked fine with no problems connecting to the internet through WIFI. Recently my home network would not connect. the network shows up on the wifi search I click connect I type in the Network password and it says incorrect password.
I checked my router settings and even removed the WEP security and changed the network to none, so even when i try and connect it says...unable to connect to this network. I have also tried to connect to other wifi networks at different locations and they also dont work.
I have restored my iphone and still no change, I have also restored the network settings and still nothing...
can anyone help?
3G iOS 4