Let's start with your OS.
If you're running the 64 bit version of Win10, you should consider installing FS9 directly to your main drive (ie, C:/ FS9).
FS9 seems to be happier if you
don't install it to the Program Files (X86) directory.
Next up, you defiantly need to install the 9.1 update patch and the "no CD" patch.
I run my install in compatibility mode. Some folks don't, but it seems to work better for me.
Once you have all of the files installed, find the main .exe icon inside the main FS folder and right-click on it.
Select the Compatibility Mode option and then try "Win XP Service Pack 2" and make sure you select Apply.
"Win XP" mode
should work. If you still can't boot FS9, try "Win 8" ort even "Win Vista" modes.
You may need to also enable "Run As Admin". This isn't the end of the world. I use this option and all I get is an early "Are you sure?" pop-up when I start FS.
Just hit "Yes" and before long you'll get used to it like it isn't even there.
Once you can boot FS, you'll want to tweak some graphics if FS looks like its running choppy.
Something I accept as a universal truth, FS runs better when the resolution
matches your main desktop settings.
On my install, it seems much happier running the same resolution and running in 32 bit mode instead of in 16 bit mode.
So, once you can launch FS and you have the graphics mostly dialed in, you can still have some crashes. DON'T PANIC.
Every time FS crashes, Win 10 will make a note of that and send a report back to MS.
Give it some time. Windows will get some updates from MS after a couple of days to maybe a week.
Last of all, don't give up.
Most of us on this forum can help you out.
All we really need to know is which version of Win10 you're running (32 or 64 bit) and what kind of graphics card you use.
With CPU's that are at least ten years old, you don't really
need a GPU to run FS9.