Network crash?

[Vaskeklut]

Hey guys.

Im not good at this, I dont really know whats happening, so excuse my noobie approach, but this is what happens.

We live in a house devided in 2, and we share the same internet and home central. From that central 2 cables run downstairs to us, one for TV signal and one for the internet. 
TV goes straight to our decoder, never had a problem with that.

The internet cable goes into my switch, were I have my desktop, smart TV, home cinema receiver and wifi point cables connected.

 

So we are sitting on the couch watching a movie on the google play movie app. 
Then everything looses connection. Our upstairs neighbor does not. The error on my desktop PC is "ethernet does not have a valid ip configuration". Wifi says connected but no internet. 

Now this has happened quite a few times, and I realized today, that if I unplug the ethernet cables for TV and Desktop from the switch, the wifi point gets connection. As soon as I plug in either the TV or the Desktop, it goes away. 

 

So I googled the desktop error and found this: http://troubleshooter.xyz/wiki/fix-ethernet-doesnt-have-a-valid-ip-configuration/ 
I did step one. 
Fully restarted my TV. Plugged it all back, and now its fine. Like nothing ever happened. 

My question is, what is causing this, and how can I make it stop? Its getting really annoying.

Thanks!

[Lurick]

Hmmm, could be a few different issues.

The cable that goes to the switch, is that connected to a modem, router, or modem/router combo unit? What model?

The router for wifi, what model?

[Vaskeklut]

@LurickA router from a Norwegian company, its just called altibox. Tried googling it, but I cant find it, we have an older model and not the one the company sells with their network packages today.

My wifi spot is called airties 4920.