|Check in Device Manager on the laptop. Is there an exclamation point beside the wireless interface? If yes, then there's a physical problem with it.|
If not, verify if you can actually see your wireless network. It could be something corrupted in the TCP/IP stack and it's no longer seeing the wireless network. If such is the case (you're not seeing your WLAN) then try uninstalling and then reinstalling the TCP/IP stack.
If that doesn't help, check to ensure you have the most recent wireless NIC drivers for your device.