I also use modded xboxs but the Media Player I mentioned above does pretty much play anything you could want it to.

Peale,
Sounds like you are broadcasting your wireless router's 'ssid' without any security.
If I were you, I'd change everything that connects to your network to static ip, for a home sized nw, its easy to manage and less troublesome to troubleshoot should you need to. Hide your SSID, as long as YOU know it there is NO need to broadcast it. You should also setup security, if you don't want to then I would set your router to only allow specific mac address' to connect.
The fact that you will have stopped broadcasting your ssid and only allow authorised hardware to connect to your router should stop people connecting. Before you do all of that (should you choose to do so) change your ssid. Its all well and good hiding it but if your neighbours already know it they are on the right road to connectivity.
.....and don't forget to change your routers admin password.
I've worked with networks for around 15yrs and have configured mine at home in the way mentioned and have not been hacked/attacked since doing so.
Just my two penneth.
Hope this helps
Stace

edited to make sense
