I have two connections and one problem:

2) first is my Internet connection:

My computer ( > Router (LAN address: WAN address: > my ISP

1) second is my LAN connection:

My computer ( > Other LAN computers (192.168.0.*)

The problem: when I have only Internet connection switched on I am able to connect to the Internet, but when I turn on also the 'second' (LAN) connection I have no Internet. It appears that windows starts to think that it should use the 'second' connection to access the Internet. How to "tell" :) windows that it should use 'first' connection to connect to the Internet?

Thanks in adv.

Check in internet properties>connections
It shows that connections or not...if not then configure it.

You have misunderstood my problem:
I have both connections configured.
Both have 192.168.0.* address.
Windows cant figure out which is the Internet connection.
My problem: How to tell windows which connection to use.

Thanks for trying, though!

The key idea was to change the 'metrics' of my network interfaces - interface that is supposed to connect me to the Internet now has lower metric than the interface connecting me to my LAN. Now windows knows which connection to use as Internet connection :)

How to change the metric see (it is exactly the same problem solved):
sorry that not in english :( , but pictures are very helpful

or in english (but more complicated):

Thats Great :)
Thanks for putting a link here...