Router Connections
All routers have one or more ethernet connections for the computer side of the connection, some may also have a usb connection.
If you have both usb and ethernet connection, then you only need one of them connected to a PC. In order for the usb to work, the software (disk) must be loaded (usually before the router is plugged in). It is important to check the instructions that come with this kind of router before plugging it in via the usb port.
If your computer has an ethernet connector then this is the best connection to use for a broadband router. Less software is involved in running a router via an ethernet connection. Windows computers will normally indicate when they are connected to a router or network hub with an icon in the lower right hand corner. Also the router or hub will often have an indicator for each ethernet connection and once the computer is connected (sometimes even before it is powered on) there should be a light to tell you that the connection seems ok.
'Seems ok' because it is possible for a damaged cable to show up as a valid connection, but fail to work properly.
Router Settings
Routers are often configured by the ISP before they send them out. They often include software that will configure your computer and confirm any broadband password.
If you have a router that was not configured by the ISP then often the default ethernet settings of the computer will at least let you talk to the router and enter any broadband username and password.
This is usually done via a web browser. If you don't have the router manual, then you will need to contact the supplier or manufacturer as there is often a password needed to
make any changes to the router. If you can't get access to the web via another machine or get hold of the router details another way, these often used defaults may help.
If you can find your ethernet connection status (usually by right clicking on the network icon for the l;an connection), you should see an IP address for you computer if it is similar to one of the ones below, there is a good chance that your router is connected and has provided an IP address - If your computer has an address of 192.168.1.3 then your router will likely be at 192.168.1.1.
If you find that your computer has no IP address setting or that it is does not start with something like 192.168 or 10. then it is possible that the router is not sending an IP address, your computer is not set to 'obtain an IP address automatically' or there is a problem with the router or the ethernet cable.
Open up your web browser ( you are bound to get a 'page not found or similar error), in the address bar try the following addresses (or if you know it, the one closest to your computers IP address):-
http://192.168.0.1
http://192.168.1.1
http://10.0.0.1
http://10.0.0.2
These are all common default router addresses. If one of them corresponds to your router address, you should see a prompt for a username and login, if you are really lucky, it will also include something like 'default/1234' in the message wich is the default username/password.
If the login message offers no clues then it is worth trying admin, user, or default as a user name and password, passwd, 1234 or possibly the router manufactureres name as a password.
If the above fail, then you really need to get to a computer with web access and search for the router make and model.
If the router ip address or password was changed after it was installed, then without knowing these details it is very difficult to get back in and change any other settings (such as the broadband password when you change ISP).
Most routers have a way of resetting these details to defaults by pressing a button (or hidden button) whilst switching on the router - however, without the router manual, clearing the settings may not be any help!