Can't connect where? sa wireless router? any wireless router? The reason I ask is, kasi baka router yung may problema, or the router settings might have changed.
Now if you are unable to connect to any known working wireless networks, that's the time we look into your notebook's wireless issue. You can try uninstalling and reinstalling the wireless drivers. Last resort would be to "reseat" (bunot tapos balik) the wireless card.
