Avery complicated one for the tech heads

I'm big into Flight Sim X. I installed the game on XP and all was fine. I upgraded to Vista Ultimate and the game doesn't work.
It says FSX failed to start due to an error with it's side by side config.

I have ran it in xp mode, updated my drivers , re-installed it , added the euro sp1 patch. Stll it does not work.
Microsoft want £40 quid to solve the issue.

Any ideas ??????

Im a bit too old to be a paper boy but thanks for the comment.

Why dont you send me a cheque for 40 quid you cheeky scamp