Turn on my internet

I am working on a new laptop that is using windows 8. The internet have been working just fine for the longest time, but I got up a couple days ago and found that it is not connected to a network. I can’t seem to find a way to connect to any network. It looks like some one just turned off the internet. The last time I saw that on a laptop with win XP, I was able to push an F key and turn it back on, but I can’t find something like that on this laptop. Can you help me, please?