But why would you do this?
What type of internet service and equipment do you have currently?
My laptop has internet and my computer doesn't have any way of connecting to the internet wireless and my router is downstairs where there is no monitor down there so i cannot connect to internet with it but there is an Ethernet port.
You laptop has internet from where? WiFi from the router?
Then the best solution would be a PCI or USB WiFi device for the desktop. Connect to that same router.