Try restarting the wireless router (unplug power lead - wait 5 secs. - plug it back in.
Then while your waiting for router to sync and settle down, restart your laptop.
Check that router shows no errors
If still no connection on laptop, delete existing, saved WiFi connection on it.
Then create new WiFi connection from scratch like the first time you created one.
If still no joy and you are getting an error message on your laptop, please post exact wording of it.