How could you tell if your computer was connected to a network?

You should see an icon at the bottom right corner of the moniter screen.

It would say so in the bottom corner.

The internet is one example of a "Computer Network." As a result, then a computer which is connected to the internet is connected to a "Computer Network" There are other types of computer networks...

you go to the bottm and go to internet connection hit the last botton u will see if u are or not

Just a disconnected computer