This html will describe some of the all too common things that go wrong when you are trying to install and configure ethernet cards.
Many people have a very hard time getting their ethernet cards to work.
My card won't get configured. My card passes it's test but EUSI still fails to connect. My card worked but every time my computer reboots I'm back where I started. My applications work, but my network connections seems questionable. Here is a list of the solutions and tips provided Installing Your Ethernet Card.