Time Machine Wifi connection problems

Recently I had a complete computer freeze up and had to do a hard reboot. Afterwards I was asked to Input DNS server information. I found some from the web and entered it. Since the DNS numbers have reset anyway. However in the meantime I can't connect either Iphone or Macbook to wifi. It shows the network is there and operating but won't connect. The IMac is connected by cable through the time machine and into the cable router and it has internet. I have tried to find the problem online with no success. I am thinking about restoring via time machine to just before the computer freeze a few days ago. 1. Will this restore settings to the airport utility so it will work. 2. To do a full restore I read that I need the install disc, since I started with Leopard and then updated to Snow Leopard should i use the Snow Leopard disc? 3. Does anyone have an easier suggestion.

System Information

Time Machine
IMac10,1
Macbook 5,1
Iphone 4

Try rebooting both the modem and router ?

Thanks for the suggestion. I should have mentioned that I have already tried that several times.

Solved it myself. Just reset the airport extreme to original settings and started over. Thanks all.