Syncing Up - The Magic Of Doing Nothing
If your PC and router are already on the same network and you can login to your routers web interface you can skip this and go to the Web Interface section.
Your wireless router and modem have a way of syncing up with each other on their own when you power cycle (Turn them off and back on again.) them. If your PC or wireless device is set to receive a DHCP address simply restarting it should result in it being configured with a DHCP address that works with your router.
The magic of DHCP will also configure your computer with the Gateway, DNS server and DHCP server it needs to connect to the router and the Internet. This all happens auto-magically!
Depending on how long it takes your PC to reboot this can actually take a little longer then just doing it manually but if you really hate typing in IP Addresses this is the way to go.