Hello Pete,
I stated I had exactly the same errors because I had the same error msgs..
I used your post about deleing the 3 files and "repairing " FSX which I did with the same results.
When I uninstalled FSX I also uninstalled acceleration, Checked add/remove prgrams for any service packs,
Check My Documents Applications and files for any flight sim files and deleted them.
Ran a search for any FSX files to remove them but did not find any.
I do not have a registry cleaner programs or I would have done that also.
I then installed FSX with the DVD's. Downloaded FSUIPC4 and ran it, It seemed to install ok.
When I lauched FSX it failed to load.
So I uninstalled it again, removed FSUIPC4.
Have a good Holiday