The short version: everything was working perfectly fine until yesterday. For some reason, Battle.net and Steam refuse to believe that I am actually connected to the internet. In BNet's case, I tried launching Diablo 3 and Starcraft 2, and neither one would actually fully load the launcher. They would say "Initializing..." indefinitely. For Steam, it would try to open the program, only to say "Steam cannot detect an internet connection."
Obviously, the fact that I'm here posting this is proof that I do in fact have an internet connection. I can still check email, watch Netflix and Youtube, dink around reddit, everything else I normally do, but BNet and Steam just will not recognize that I have an internet connection. I have used both on this connection before, so I'm not sure why yesterday they just decided to stop cooperating.
Here's the really weird part: this morning I took my laptop to a public WiFi spot. It connected just fine, and Battle.net AND Steam both worked fine. I then put my laptop in standby (did NOT shut it off), brought it back home, hooked it back up to the main network, and it continued working. I was still able to connect to BNet and Steam. Everything seemed to be fixed.
Then I shut down my computer. When I turned it on again later, the original problem was back. BNet and Steam won't recognize my internet connection.
So that's where I stand. I've done all the obvious fixes (uninstall/reinstall, reboot, virus/malware checks, etc). Reddit people way smarter than me have narrowed it down to either being an issue of closed ports (why the university would suddenly close them now, after a month of having them open, I don't know, but I'm scheduled to talk to tech support on Monday), or a DNS issue. I've Googled every DNS fix-it/tweak guide I can find, and done everything they said, to no avail.
Can anyone here tell me what the heck this is? Is it the ports? Is it the DNS? Is it something else? And what the heck can I do about it?
Thanks for any/all help! :)