Why can't people connect to my Minecraft server?

I recently bought a new PC and have given my previous one to my dad, as we live in the same house. Anyway, on the previous PC, people could connect to them perfectly. So obviously, I had to give my PC away, so when I set up a server on the new PC, I expected it to be fine. Which it was not. On the new PC, I setup a server normally, using Hamachi for them to connect, the same way as on the old PC and they can't connect. The server loads up fine and is on and active but they can't connect, the server is just displayed as offline. They are connected to my Hamachi network, we all have our Hamachi's turned on, I can even get on the server and they still can't connect. Also there are no error messages in the console, the server loads up just fine.

If anyone has any help as to why this is happening please help me.

Added (1). UPDATE: My firewall is not blocking anyone from connecting, I have made sure that it is not.

Can you check your internet settings on the new PC please?