Reorient the signal antenna. Plus, desktops are more likely to reflect and block signal due to the metal in their cases.
A bigger antenna for your desktop or router may be needed, if this is even a possibility.
A reduction in obstacles such as walls, electric guitars, or pretty much anything that blocks line of site between your wireless access point and desktop.
Is your desktop running the same network standard as your wireless access point? Most laptops are running some form of N wireless. What is your desktop running?