D-Link DI-524 Wireless Router

Start with the simplest answer first so make sure the laptop's WiFi is turned on.
If you have set the router to provide a closed network your laptop will not see it automatically and you will need to enter the WiFi network settings in network setup. if you are using Windows click start, click control panel and click network, on the left hand sidebar you will see "Setup a Small or Home Office Network", follow the wizard and you should be able to get connected. If you are using Mac OS X click the Airport icon on your menu bar, click "other network" and enter the SSID, select the encryption type and enter the network key (password).
Lastly make sure that if you have chosen to use an access control list you have entered and allowed your laptop's MAC address in the list before trying to connect.