FSX SP2 "Fatal Error" - Help Please

I've upgraded my FSX from SP1 to SP2 and SDK Sp1 to SDK Sp2 running Vista Ulitmate on my Dell 710-XPS with a nVidia 8800GTX video card. SP1/SDKSp1 ran fine, no problems with anything. After loading SP2 and SDK Sp2 and starting FSX, ... during the start-up process, the FSX screen appears, the music starts, the Free Flight screen appears followed shortly by a box appearing which states "Fatal Error: MS Flight Simulater has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available." Well no solution is available and I have to close the program. Reading these forums, I felt that a solution would be to check my video drivers. Upon checking I found the latest driver from nVidia,ForceWare Release 169.25 and loaded that driver. Rebooted and attempted to start FSX, got the same result; Fatal Error.Any solutions/advice from anyone.