I got FSX running no problem. Played around with it for about 20 minutes. I didn't need to do any tricks to make it work, just stuck the disk in and it worked.
When I tried to install Acceleration, it locked up and crashed Windows Explorer - which restarted itself after a few minutes, but nothing on the start menu would work. I had to hard restart Windows from within the Task Manager.
Strike one.
Second try, I right clicked on Acceleration's setup file to try to run it in XP Compatibility mode. Just right clicking on the file locked up Windows Explorer. W.E. restarted itself again, but again nothing on the start menu worked. I had to go into task manager to shut down.
Strike two.
Third time, I tried copying and pasting all the files from the Acceleration CD to the desktop to try to install it from there. I've had this work in the past, especially with slightly scratched disks - which is the case with my Acceleration disk.
It started copying the files to the desktop, said "5 minutes remaining", then it said "10 minutes remaining", then it said "16 minuted remaining". I took the dogs for along walk and came back 45 minutes later and it was still stuck at "15 minutes remaining" and the progress bar showed no progress.
I hit the cancel button on the time remaining dialogue box and surprise surprise, Windows Explorer crashed, nothing on the start menu worked, hard to go into the Task Manager to shut down.
Strike three.
I pulled the Windows 7 harddrive out of my system, hooked up my old XP X64 harddrive.
It seems to me that the 64bit Release Candidate still needs some work. I don't think in this case that it's a compatibility problem, I think it's a stability problem with Windows Explorer. The scratched Acceleration disk certainly may have exacerbated the problem, but it should not have crashed Explorer. I installed this same copy of Acceleration in my XP X64 drive no more than a month ago.