Ok try this....
Goto
START> RUN> Type in cmd, hit enter> Type in ipconfig.
Look for the default gateway, now take that IP and go to your web browser. Enter that IP in the address bar, and go to it.
It will prompt you for a password.
Type in admin for the user, and admin for the password. If that does not work you need to do a hard reset, probably because the prick next door changed it. now after getting into the router, look for anything that says password in it. After you find it, you should be able to specify a password.
Also if you want to keep that little puke out of your network, you should enable MAC filtering.
To find your MAC address go to start> run> type in cmd> type in ipconfig /all
it should be listed as physical address. Take those 12 digit addresses and put them on the filtering list. But you need to have all of the MAC addresses to all of the computers on your network, if you dont, they wont be able to access the network at all..
Now your next door neighbor will get mad, when he tries to get into your network, he cant. Next time you see him, give him the middle finger and laugh...... And be like whats up now b!tch.