24 bit error message on loading FSX

Can anyone help with this infuriating :-mad error message from FSX"Flight simulator has detected one or more of your monitors is using 24 bit quality. Flight simulator is incompatible with this display mode. Would you like to change your display settings?"Both of my monitors are set to 32 bit and no amount of fiddling around will allow the program to load. I have ininstalled , re-installed on a different drive, unplugged one monitor, changed drivers etc etc. What is even more annoying is it did not do this with the same set up prior to reinstall that was necessary following a HDD failure.Cheers DaleE6600 @ 2.40GHzNVIDIA GeForce 7950 GX22048MB RAMSB X-Fi AudioXP Pro SP2