Minecraft only allows me to play offline?

I saw another question like this, but none of the answers seemed to work, so here is my situation.

My computer is getting Internet. I am asking this question from the same PC, so I clearly have a working Internet connection. When I open Minecraft, the launcher comes up and then just says "Play Offline". How can I play online? Is something blocking it? Any help would be appreciated!

NOTE: This happens when playing from my PC and my gameband when plugged into my PC!

Update

My entire firewall is now disabled, but it is still doing this. All errors say to check the firewall and allow Minecraft through, but it is disabled (and even if it wasn't, it allows both Minecraft and Java TM SE Binary).

I am starting to think it may be malware. Any ideas for finding any malware programs that block Internet use (if they exist)?

You must be signed in to play online.

If you have a legitimate version of Minecraft then it should prompt you to sign in upon launch.

You can try checking your firewall to make sure your computer is not blocking the internet connectivity of the application.

Sometimes you do need to wait up to 20 seconds. You should see the launch button switch from Play Offline to Play.

Have you tried changing where the gameband is plugged in, I know it sounds stupid but sometimes it works

Hope this helps and have fun gaming!

Sometimes, also checking with your host or the host and see if the server has "Online Mode = True" or not. That would be on the person whos hosting the server "server.properties" file. That can also be looked at to see if thats 1 reason, other then you logging in or just checking your firewall ports, however the firewall ports are usually taken care of once you log in to minecraft connecting to a world, your firewall should pop up and ask you "Accept or Not Accept." Those are the only 3 possibilities thats preventing you from logging in. It WILL be one or the other.