Okay what you're going to do is click on the wifi bars in the lower right hand corner and a green column should come up on the right Side of your screen. Click on the network that's yours(for example "belkin.wireless")
once you've clicked on the name that your Internet is called it should expand a little bit and there will be a box labeled "connect automatically" and just click that box and then hit connect and now it should connect automatically as long as you want!