Instructions
Open the GameBurnWorld site.
Click the link that says "FLIGHT SIMULATOR X v1.0 [ENGLISH] NO-CD/FIXED DLL (1.12MB)."
Click one of the mirrors to select a site from which to download.
Click "Click to Download File" from the next screen, then save the file somewhere easy to remember, such as your desktop.
Double-click the file to open it.
Copy the three ".dll" files in the archive to the main directory of "Flight Simulator X," which is "C:\Program Files\Microsoft Games\Flight Simulator X" by default.