5mb, as DBTL mentioned - have you got the correct driver for the network card installed?
Next, assuming the drivers are correct, is the card configured correctly - at a minimum, you should have Client for MS networks and Internet Protocol (TCP/IP) installed.
The network properties for the card are the next things to check - I assume your Belkin is providing IP configuration via DHCP, so both Obtain IP address and Obtain DNS information should be set to automatic.
Assuming all this is correct, you can confirm the network properties by opening a command prompt and typing ipconfig /all. You should get see a valid IP address (probably 192.168.0x.x), default gateway (the Belkin) and the DNS servers from your ISP (vis the Belkin). If you have an auto address 169.x.x.x or a 127.0.0.1, then you are not receiving the information from the Belkin via DHCP.
If your Belkin is NOT configured to provide IP information via DHCP, then you will need to supply all the information yourself - it will be identical to your laptop, except for a different IP address to the laptop.
Assuming that all the settings look correct, try pinging the belkin from the desktop.
The only other thing that could be causing problems is the firewall - disconnect the belkin from the internet, then disable the firewall on your desktop, then run through the above to see if you can connect.