To set a static IP on your Windows computer: Click Start Menu > Control Panel > Network and Sharing Center. Now it restricts chats and some online features.
It changed when we got a new router. Type in the IP address default gateway, subnet mask DNS server addresses you want to use. Without setting up a static ip address port forwarding will probably work when you initially set it up, but after restarting your PS3 it may get a different ip address.