Unable to set up Belkin wireless router to desktop pc.?

I have recently bought a Belkin wireless router. I have followed the installation guide and on screen instructions however i cannot get a connection to the internet. The router is connected to the PC via an ethernet cable (presumably so you can enable the wireless option once connected to the internet). I have confirmed with the ISP Tesco's that i am using the correct username and pword but the onscreen instructions to install defaults back to question whether i have the correct details to be able to connect to the internet. It is not clear exactly what the problem actually is therefore it is difficult to resolve. Does anyone have any ideas, all suggestions welcome, is there anyone else who has had similar problems in setting up with both belkin wireless routers and Tesco's or any other ISP if yes how did you resolve this issue?