Windows 7 works with a wide variety of networking settings, so it is not necessary to configure most advanced settings. However, changing the default username and password as well as the default wireless networking name are important before connecting any of your personal computers to the wireless network for all to see.
First, access the Security or Administration configuration screens to change the password and username required to access the router and its configuration. This will prevent someone else from logging into to your wireless router and changing settings without your permission.

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Next, go to the wireless configuration settings and choose a SSID or wireless network name. This is the name that will appear in Windows 7 networking when you are choosing which wireless network to connect to.
If your router supports DHCP and you intend to use it to make your home networking easier, configure that as well. Use an IP address range compatible with your current networking address scheme, or if you don't have one, use something like 192.168.1.10 to 192.168.1.50. Make the range larger or smaller depending upon how many devices you have connecting to the network. Be sure to create a range that has more addresses than you have devices as wireless network connectivity drops or issues might cause an address to stay "in use" on the router even though the device no longer thinks that has that address. Having a buffer of a few addresses ensures that such devices will be able to connect again later.
Finally, secure your network using a wireless network security protocol. You may have read that such security can be easily broken, and that is true, however, the number of people who can do such a thing (and might actually try it on your network) is not as large as you might think. Implementing basic wireless security protocols is like locking your doors. A professional burglar can still get into your home by picking the lock, but someone just walking by trying doorknobs will not.
Windows 7 supports all current wireless security protocols, but most users report the least amount of trouble using WPA Personal. If you cannot get WPA2 to work with your wireless network, try using WPA and see if that helps.