Spotify attemped to access my computer, but Windows Firewall blocked them.
Hackers use open ports, which are holes in a firewall.
If Windows Firewall had not blocked Spotify, or if I made a mistake and allowed Spotify access, I would have enabled hacking.
The following might be helpful.
Note the path at the top; Control Panel/System and Security/Windows Firewall/ Allowed Programs
Spotify .exe is not checked
Windows Firewall blocked them
Here's an enlarged view of the same thing:
If programs can access your computer, they can allow others to see what's on your computer. They can use your computer to send spam, or whatever they wish, while it's connected to the internet.