@DenisDA: why not try to make the built-in LAN work? This is madness, what you are trying to do, you and the member that started this thread. It is like re-inventing the wheel. I guess people will never stop making things difficult. What makes you think an USB lan will work, if the built-in did not? Rather than to try to fix your ethernet you want to use an USB LAN.
A good router will take care of any of your problems.