http://192.168.2.1/
It should bring up your router configuration information screen.
The proper address will vary by ISP / router model.
To find the one that applies to your setup, open a command prompt (Windows-key R; enter cmd in the window). Type ipconfig. You should see something like this:
Microsoft Windows XP [Version 5.1.2600] (C) Copyright 1985-2001 Microsoft Corp. C:\Documents and Settings\cynwoody\desktop>ipconfig Windows IP Configuration Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : IP Address. . . . . . . . . . . . : 192.168.0.2 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.0.1 C:\Documents and Settings\cynwoody\desktop>The address in red is your router. That's what you should type into your browser location box. Hopefully, you will see a login screen of some sort. Try leaving the userid blank and entering admin as the password. If that doesn't work, find the manual for your router (probably available on the net if you can't find your paper copy) and see what the default combination should be. You may need to hard-reset the router to get it back to the default.