Geary
This is possibly going from sublime to ridiculous...
I have a second hard drive, on which is a minimum install of WIN XP. Installed under that is my "hardcore" FS9 installation.
This contains no rubbish, only my favourite textures, sceneries, and (relatively few) aircraft.
To get there you need to change the boot disk order in the BIOS (by pressing Delete during reboot and selecting it).
The sim does not recognize other copies of FS9 and FSX (Now on the "E:\" Drive under this OS).
It's a wonderful debugging tool, but also the best simming experience under the sun.