The Tesco page, could be a cached page..
Does the router, give you any kind of status, i.e "connected"
Are there any lights on the router, i.e, power, sync, etc etc
I would also suggest clearing your cache so you get "real" results.
If you are on vista, do this:-
Click start, then in the search box type cmd, at the top of the start bar, right click on "CMD.EXE" & click run as administrator.
In DOS, type:
ipconfig /flushdns
Once done, click close.
Now try and visit a site, for example
http://www.google.co.uk
If you get "google" then I would suggest:
* Check your firewall status on the PC. If there is one.
* Check any anti virus / spyware / malware programs you may have running.
OR:
Go back into DOS
and type ping
bbc.co.uk
If you can paste the results and any more information you can provide us with, one of us, should be able to resolve this.
I would also apeak to your ISP to confirm all the necessary settings, they will probably say something like "third party routers arnt supported" just get the settings and re-enter them, if need be, reset the router, should be pin whole somewhere.