[Rob]

Ignore the wireless side of things for now - if you can't see browse to the router's config screens when wired there is no hope for wireless. The inability to browse to the router config shows it has to be a router <> computer issue.

If you have played around with the router settings at all (difficult if you can't browse to it), do a factory reset - many router have a little button on the rear somewhere.

flush the current IP from your computer's ethernet card - command prompt ipconfig /release, then reboot the computer, having reconnected it to the router.

If you still have a problem please use the command prompt and tell us the results of "ipconfig /all", when the computer is connected to the router.