Looking for Remote Desktop application
If you've got XP Pro, remote desktop is simple enough.
UltraVNC is another free solution that works well. You'd have to install the server on your desktop, and then a VNC viewer to access it. I believe there are some VNC clients that are standalone and can be run off a USB drive, but I'm not sure.
Desktop:: 2600K@4.8Ghz/GTX 980/16GB RAM/250GB SSD/4.0TB Storage/R5 Case/Win 10
Laptop:: Lenovo T450S (2015)/256GB SSD/8GB RAM