I'd say just ring up your ISP. If it's a decent one they should help you determine what sort of issue it is, and if it's DDoS/DoS attack, it's partially the ISP's responsibility to defuse it.

But then you also mentioned that you can't connect to ANY wi-fi. That means it's not the internet that's causing the issue, but your PC. As Elite said, try to get rid of any viruses you have, and if that doesn't help, you could get better help in computing forums rather than here as it's not Toribash related problem.