UltraVNC has a "Single-Click" version which can be configured to automatically connect to a listening VNC server. You can download an UltraVNC client for Freelock here: http://freelock.com/ultravnc-fl-sc.exe. Note that this is a Windows executable, and if you're using Internet Explorer, you may need to right-click on this link and click Save Target As to download it to your computer.
Once it's on your computer, simply give us a call, and double-click the file you downloaded. We can talk you through the rest. There is nothing to install or uninstall--when you're done using it, you can simply delete the file.