Unknown people appearing on my network.

Lately I have seen 2-3 users that are unknown to me appear on my network.I have tried everything possible to let those names disappear.

The Mom-PC and HP-PC are the unknown. (Regardt-PC is me).

So here's what I did:

1- Setup a WPA2 security (changing the password up to 4 times)
2- Setup a MAC filter ( allowing only me, my parents 2 laptops and 2 smartphones)
3- Changed router password

After that I ran a program called LAN Spy to give me results on who's connected to my network. The only results to show up were those which I knew. But if I access my network and sharing center, I can see the two other PC's. ( HP-PC and Mom-PC)

I have really tried everything I got suggested and so far nothing has worked.
Would really appreciate some feedback on this issue.

Thanks

This could be due one of the PCs connected to your wireless network is associated - by away or another - to some other PC that is not connected to your wireless.
For example, you may have one PC that is connected to your network wirelessly but is connected to some other network through the wire. The connection may be bridged between wireless and wired when you do the sharing stuff. Looking for available share folders uses multicast so the discovery packets reach more than what you have connected to your network.

HTH

Amjad

Make sure you are using a complex encyption phrase