Today my laptop suddenly stopped connecting to my wireless (Belkin) router upstairs. Kept on telling my I had the settings wrong, and I kept on putting in the right settings, and it wouldn't recognise them.

Tried a system restore to yester5day when everything was working fine. Finally I went upstairs and and disconnected and reconnected the router - and suddenly everything worked fine.

It appears that the router had stopped putting out a wireless signal, for some reason known to itself.

The old principle applies - when in doubt, reboot everything.