|Is DHCP configured on your router?|
Is the NIC on your desktop set to get it's TCP/IP settings automatically?
The answer to both should be "yes" and then your desktop would get it's settings from the router and would be able to access the LAN and the internet.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.