Error messages on instlling MS Flightsim X

When I was running Windows 7 7000 I was able to install and use MS Flightsim X OK, now running Windows 7 7100 I have been having trouble installing FSX. When it got to the end of the installation for the first time a error message came up saying:

Failed to load Error #0x80040707
Description: DLLfunction call crashed:
Dsetup.DirectXSetupA
Setup will now terminate.

Looking in the instalation dir many of the exe files were missing. Well I thought I would give it another go.
This time it got a but further before I got the following message:

Failed to load DLL 0x80040702
GameuxInstallHelper.
Setup will now terminated.

When I went into the directory I found it had installed the exe files this time, so I gave it a go and indeed it does work.
But I still wonder if something might be missing and why did the installation terminate giving me the impression that it had indeed failed.
Like I said before the simulator worked very well with Win7 7000.
I wonder if others have had the same trouble installing FSX with Windows 7 RC 7100?

my setup is:
Motherboard - Gigabyte EP35-DS3R
Intel Core2 Duo CPU E8400 @ 3.00GHz
Graphic card - Asus EN9800GTX+
Ram - 4gig
x64 based computer

regards
Richard

Since writing the above I have looked in the Windows Control panel\ Programs& Features and found there is no mention of FSX being installed. FS2004 is there OK but not FSX. Very odd.

Have you installed the nVidia drivers for Windows 7 and also the compatibily mode.