Delete all cache, cookies, history and etc from browsers and try again to access the router. Also if you denied some scripts ( for instance javascript ) try to enable it and try again!

Hmm. It appears to have solved itself. I did an ipconfig /renew and then an ipconfig but I thought it was still not working after that but I may be wrong. Perhaps it's one life's great unsolved mysteries.

See, check & tell me that how old is the router you are using.. If it is one or more than one year pld then i will suggest you to download the latest firmware for the router.... I guess it is Linksys.. It works...

Yes it is a Linksys, and it's probably more than 1 year old. The firmware version claims to be v7.00.4 and the latest is 7.00.6. According to the release notes, 7.00.6 doesn't fix anything relevant and since it now appears, I repeat appears to be working I guess I'll leave it unless or until I get a problem.
Thanks for your help.

My mp4 zen touch two does not connect to wifi