While I was out of the house, my father rearranged the network cables a bit. I don't know what he has done exactly - He says nothing more then pulling and untangling.

When I came back home, my internet connection changed its IP from 192.168.0.205 to 169.254.197.233. The speed changed from 1Gbps to 10Mbps. It has also been at 100Mbps for a while. My subnetmask changed from 255.255.255.0 to 255.255.0.0. The standard gateway changed from 192.168.0.1 to no standard gateway. My DNS servers remain the same.

I have checked the lights of the UTP ports, and it looks like it's only sending a heartbeat every few seconds.

A sketch of the (relevant part of) the network:

My PC ----- extender ----- modem
        ^      ^       ^        
      Wired    |     Wired 
               |    
        This thing connects 
      two cables to each other

All the cabling is gigabit, my network card is a Realtek RTL8168C(P)/8111(P) Family PCI-E Gigabit Ethernet NIC (NDIS 6.20). THe modem is a CBN SVG6540E

I have no idea what is going on here and I don't know how to find out either. Any help is welcome! If you need any more info, please ask.