Router don't need installed per say. The disk just makes configuration easier. Read your manual and you should be able to find the default IP address user name and password for the router.
You can then use your web browser to configure the router. So if you manual says the defaults IP address is 192.168.0.1 you would open your browser and in the location bar type: https://192.168.0.1. and it should take you to a login screen where you can use the default user name and password to get in. Don't forget to change your password once you are in.
1. Plug the ethernet cable coming from your modem into the internet port of the router.
2. Take another ethernet cable plug it into the ethernet port of your computer and then plug into one of the 4 remaining LAN ports on the router.
3. Make sure the computer is set to obtain an ip address automatically. Right click on network adapter select properties double click on internet tcp/ip and make sure it is set to obtain an ip address automatically.
4. Unplug the power from the modem router and shut down the computer.
5. After a minute or so plug in the modem 30 seconds later plug in the router and 30 seconds later restart the computer.
6. When the computer comes back up click on Internet Explorer and run the setup wizard.
How To Configure Buffalo Router Without CD?