Thanks for the advice. The connection speed is pretty much back to normal and I only got as far as changing the channel and the DHCP scope. I may introduce the security at a later date if my grandaughter and stepson can be persuaded to learn another password
BTW the grandaughter's I-Book found the router straight away, before my laptop had even started up (after we turned them on at about the same time)...I'm seriously thinking of getting me an Apple...v impressive