Help with mac their are shared comps in finder windows

[sekz]

I see comps being shared with my comp without my permission i know that one is my sister but she has a pc and she didnt connect how can i make those comps unshared. The picture below is what i'm talking about

 

[Tallest Skil]

Password-protect your network? Turn off sharing? We need to know more before we can tell you how to stop this.

 

[BlueRevolution]

You're not connected to them; your computer is just aware of their presence. You will still need to authenticate in order to connect to them. They cannot connect to you unless you enable file sharing in your System Preferences.

But yes, if you have a wireless network, you should ensure that it is encrypted.

 

[count chocula]

You're not actually sharing anything with them. Finder just lists them because they are on the same network and if you choose to you can connect to them.

 

[JNB]

They're sharing to you, not the other way around. Relax.