Calm down, take a breath and try shutting down your computer and restarting it. While you are waiting on that unplug your modem and ( may be one box ) router for about 5 seconds and then plug them back in again.
Then tell us what messages you get about connecting.
reason could be overheating of your router. Try switching it off for 15-20 mins and plug it back in and then try connecting to wifi . Also try connecting to wifi through your cellphone and check if it works. If it works with your mobile then the problem lies within ur pc