Can't connect iPhone to Wi-Fi?

Can't connect iPhone to Wi-Fi?

Go to:

Settings > General > Reset > Reset Network Settings.

Can you be more specific?
I know some old model have Wi-Fi problems.
It happen to me once, and it was caused by dampness.
I just can't choose Wi-Fi in my menu.
so I went to the apple store and exchanged for a new one.

Being more specific would help us allot rather than asking a question with no details provided at all. This seems quite lazy and is more likely a waste of time for those looking to answer it.

Connect your USB cable to your computer but not to the iPhone, iPad, or iPod touch until step 3.
Turn off the device: Press and hold the Sleep/Wake button for a few seconds until the red slider appears, then slide the slider. Wait for the device to turn off.
If you can't turn off the device using the slider, press and hold the Sleep/Wake and Home buttons at the same time. When the device turns off, release the Sleep/Wake and Home buttons.
While pressing and holding the Home button down, connect the USB cable to the iPhone, iPad, or iPod touch. The device should turn on.
Continue holding the Home button until you see the Connect to iTunes screen. When this screen appears, you can release the Home button:
USB cord pointing the iTunes symbol
Note: If the image of a battery appears, let the device charge for at least ten minutes to ensure that the battery has some charge, and then start with step 2 again. If you don't see the Connect to iTunes screen, try these steps 1 through 4 again.
iTunes should automatically open and display the following message:
Alert text: "iTunes has detected an iPhone in recovery mode… "

Once change ssid name of your router