I can't join any Minecraft server. What's wrong?

I can't join any Minecraft server. What's wrong?

Added (1). I have premium Minecraft and i have had this problem for a very long time. I wait for servers to ping but it says it can't connect to the server. I have checked the firewall and it's all ok. I really need help.

You may not be using the correct/same version of Minecraft (the same version of the server you are trying to join) which you can change where you log on, on the left hand side. Default is to use the latest version. Some servers like to use older versions of Minecraft, and their server may come back as offline if your not set to the right version as well.

I don't know… It says something about java