LAN sometimes works and sometimes doesn't: IP problem?

I have a little network at home, with the main internet access in the living room (cable, not wireless) and a router for the PC in my study.

For years I've had an internet provider that required me to use certain IP addresses, assigned to me by that provider. It worked perfectly fine all the time.

Now, for several reasons, I have a new provider. This one requires auto detection for the IP address (or whatever it is called in English, "Automatisch beziehen" in German). And now I often have connection problems on the PC in my study, which is connected via router. Then I can't access the internet. Windows shows me my usual connection which is called Network 2 and tells me it has no connection, and it also shows me a new Unidentified Network which it obviously created by itself which also has no connection.

Unplugging and re-plugging the network cable doesn't help; Windows does a new network scan then but the problems remain. I have to re-boot, sometimes even two or three times, and then all of a sudden the Unidentified Network is gone and my regular Network 2 is working again.

I got a brand new PC with a fresh and clean Windows installation and I'm having exactly the same problems with this machine as I did with the old one.

Does anybody have any suggestions for me?

Can you provided an IPconfig /all output. Use option 2 from the link below.

How to run Ipconfig /all

Can you also provide a screen shot of your adapter settings?

Is a modem running your main connection in your living room or another router?

The only thing that should change is your router configuration to get the IP address from your isp should be changed from static to dynamic. This only needs to be done on your main router, If you have 2 routers setup you need to make sure that DHCP is NOT setup on both routers.

From your description I'm not exactly sure how your network is setup. It would greatly help to know each device that you have on your network and where its plugged in.

Thanks a lot, I really appreciate your help

Here is what Ipconfig gave me:

Can you also provide a screen shot of your adapter settings?

Click to expand...

Sorry, it seems I'm being a bit dense, what do you mean by that? Which adapter?

We only have one router. The setup is like this:
In my living room the company installed a little box that gives us broadband internet and cable TV (the company is called UPC, I don't know if they're also active in the States). From that little box a cable goes to a router, which actually is a sort of cable modem. That also was provided by the UPC company.

From the router we have a cable going directly to the PC in the living room. There the connection always works fine.
Another cable goes from the router to a Powerline ethernet bridge that provides the connection to my study. In my study the network cable is plugged into the Powerline ethernet bridge plug on the one side, and on the other side it's plugged into my PC.

Do you think that might be the problem? With the fixed IP addresses the Powerline bridge has always worked.
The problem is that we can't use wireless because the signal doesn't arrive in my study, and using a cable would be extremely awkward because of walls and built-in furniture. The Powerline thing was the neatest, easiest way so I'm hoping I will be able to keep it...

Need to know the modems Make and Model and if you have a separate router the make and model of that also.

Also what type of service did you have before, DSL or Cable, and what type of service you have now, DSL or Cable.

Sorry for the delay, got sidetracked by family stuff.

The modem/router is a Thomson, and the sticker on the bottom says TWG870UG.
There is no other device in the network besides that Thomson thing and the ethernet bridge plugs.

And before we had DSL, now it's cable.

Sorry for the late reply.

I have to say I'm not very familial with Powerline ethernet bridge since its not something I actually see in the US.