CTD - FSX on WinXp Pro.

Had a search through the forums, can't find anything quite like this so any help appreciated.I'm getting a CTD in FSX whenever I try to Load or Save a config file from the settings menu, or when I try to Add or Edit an Area from the Scenery menu. Basically whenever the standard windows explorer is accessed.I get an immediate CTD, no errors or even a slight pause - it goes straight to the desktop.I have recently upgraded my video card, from an Nvidia 7800GT to the 8800GTS, and I think it is at this point that this problem has started. Tried 158.22, and 158.27(beta) drivers, re applied Apr DirectX and the C++ runtime as per other CTD threads. Have tried a complete FSX + SP1 uninstall and clean re-install with no add-ons, but it's still the same.FSX works great apart from this very annoying problem. Getting between 25-35FPS in any area I fly and it feels smooth. I wouldn't mind too much, but I can no longer add any scenery! No other games or applications have any other problems.Anyone else with a 8800 getting anything similar? - as above any help appreciated.Cheers,AndyAMD 64 x2 4400Asus A8N32-SLI DeluxeBFG 8800 GT 320MB4GB DDR (3GB usable)Creative SB X-FIWinXp Pro SP2 - fully patched :-)