Follow-up... I still have not been able to get Add-on #3 to install on my computer. This includes trying the following provided by their TechSupt department:

VERY IMPORTANT!!! Before installing/updating RealFlight or any of the Add-Ons Volumes please make sure you have closed down ALL background applications. Every Icon you see next to your time in the lower right hand corner are running programs and need to be exited, closed, shutdown, etc. To do this simply right click over these icons and select the command to shut it down or disable the program (please refer to your users manual for the program).

For Windows XP users also do the following:
1. Hold down Ctrl+Alt and tap Delete. This will bring up the Windows Task Manager.
2. On the Windows Task manager select Processes
3. In the processes list click on User Name so that it sorts the processes by the User.
4. Look for your log-on (user name)
5. End Process all of the programs that are running under this log-on by -
a. Click on the processes name and click on End Process
b. On the next prompt saying Yes.
6. Leave Explorer.exe, Taskmgr.exe, and if you have it Rundll.exe (or Rundll32.exe)
NOTE: Only End Process the processes that are associated with your user log-on. Such as the ones listed above.
7. You can now install any program that you wish without any interference from background applications.

I also call the TechSupt department and was "stepped through" the above process and still no luck. The young lady there stated that there was nothing else they could do and offered to refund my money on the Add-on disk.

I then drafted a message that I sent to both the GreatPlanes techsupt site and the RealFlight site a few days ago - no response so far:

I have been through all avenues and still can not install Add-On #3 to my G2 system on my XP computer.

I have followed all instructions received via other correspondence (Including going to Task Manager and shutting down all background programs - that standard email you send to all clients reporting this issue).

I contacted TechSupt by phone and again completed all the "special steps" to install this add-on. The TechRep said there is nothing else we can do but refund the money for the add-on. To this, I say BUNK...

As a software engineer, it is immediately apparent that the Add-On #3 disk performs a different install set of instructions than do the other 4 Add-on disks to which I have no trouble installing - this shows that there is nothing wrong with my computer or the software I have installed on it - it is a bug in the installation on this particular version.

I also know that there is a method to manually install the needed files from the CD to my computer - I just need to know what it is. I really want this add-on as I am currently building an A-10 and that aircraft is on the Add-on 3 disk.

Can you PLEASE forward this message to your engineering folks and have some one contact me to assist in the installation of this product. Come on folks - help a fellow programmer and hobbyist out.