Hmm, I'll offer what help I can.

Most of what's contained in the second screen is often provided by your ISP or whomever is in charge of maintaining your internet access. See if you can track down a setup document or there is someone you can contact if you need to verify that your settings are correct here.

On your third screen, the "SSID" is the name of your router/network that the computer connects to. You should change this to something other than the default so that others cannot guess it. The "SSID broadcast" selection is referring whether you want your router to announce it's presence to the rest of the world or not. When you open up a network connections/wireless settings dialog on your computer and tell it to search for available networks, it's looking for routers that are broadcasting their ID. Setting this to "No" will prevent your router from advertising its presence to the rest of the world.

Your fourth screen has to do with using a security key to further prevent access to your network through your router. By setting up an encryption key, every computer has to have that key entered into the wireless setup for your network to connect to it. Basically it's a password that allows your computer to connect to the router.

NOTE: You should play with these settings via an ethernet cable connecting your router and computer. If you turn on your security while you're connected wirelessly you could lock yourself out of your router until you update the associated security details on your computer so it can connect and you'll need to connect to the router with an ethernet cable to get back to your router, so you might as well avoid this step.

<b>EDIT:</b> It looks like you might have already locked yourself out wirelessly, so use the cable.