Is someone breaking in to my computer?

[TomS]

I don't know anything about computers and English isn't my main language, so apologies in advance for any mistakes!

Context
I live in a student room, and there's several other people in this building. To have access to the internet, we all have to connect a cable to our computer.

Problem
Whenever I open File Explorer (Windows Explorer) and go to Network, there is my computer and someone else's (always the same person) computer.

I don't know what it means that his computer is there...

• Did he do this intentionally or is it something that happens because we all have an internet cable (though there's several other people here who have a cable and their computers don't show up in Network)?
• Can he get in my computer now? Can he see my documents, see what I do on the internet? Break into my webcam? Etc...

Thanks for your help in advance!

 

[Troncoso]

It means he's allowed his computer to be viewable on the network. That setting should be turned off by default. If you click on his computer, you may be able to see some things that he has, but unless you turn on network sharing, he won't see anything from you.