There shouldn't be any settings that you need to fiddle around to get wifi working. Just turn on, and connect to an access point.

Try this, tap on the arrow next to your access point name, scroll to bottom and tap "renew lease". See if it fixes the problem.

If that doesn't work, try "Forget this network" and reconnect.

The last option is to restore the phone. Which i think will most likely fix any problem.

My favourite way to perserve my contacts is to sync with Windows Address Book in iTunes. This way, it preserves the name fields (First Name/Last name/etc).

You can try looking at this or this (#4) for contacts backup via SSH.