My Windows XP notebook won't/can't connect to the internet?

[spandexation]

I've been using that laptop for well over two years and all of a sudden the internet has stopped working. The wifi is turned on, but it still says that it can't find any networks. On the off chance that it DOES find internet, it doesn't go through when i open up mozilla or internet explorer. Do you guys know what i could do?. Thanks in advanced.