How can I get my computer to connect to the internet?

My laptop says that the wifi is unavailable so I scanned for networks but it wouldnt even come up with the usual list. I also tried using the repair but it didnt work. I clicked on diagnose problem and it couldnt find anything. This happend once before about three weeks ago. So I unplugged it and waited a week, after the week it started working again. Whats wrong with my computer? I would wait a week and repeat what I did before but I need my computer tonight. How can I connect to the wifi?