Thanks Mike, yeah I will check all that type of stuff out (personally I prefer Mac Filtering and have mine all set up like that) ..... but I don't think anything has changed in the router to be honest .

Update

I know its been ages for this problem but my sister left the pc connecting via ethernet while having other things to sort out.

Anyway, after pointing her to your tutorial Mike (how to remove network profiles) everything is up and running.
She swears that profile list was empty when I had guided her over the phone but the main thing is problem sorted!

Thanks Mike and Phil

Glad she's got it sorted in the end.