Try turning it off and then on again. Make sure you login to the wifi you are trying to use if it requires a password. Does wifi work for your other devices? It could be that you have too many devices trying to run off one router. If it won't connect to public wifi like at a coffee shop, it could be your settings are wrong or maybe the antenna inside is messed up. Make sure your setting is set to "always" under "keep wifi on during sleep." If that doesn't improve it, you may want to replace the internal antenna. Hope that helps.