Curiouser and curiouser... I can't say what's causing this, but before you buy another copy of FS9, do one more uninstall, then manually get rid of
everything left behind. Don't trust the FS9 installer to do it right. I know that might seem illogical, but those four disks carry a lot of code, and the installer doesn't have much of its own. It's fallible.

But before you run the new install, get a different graphics card online- anything, even onboard mobo graphics- and disable the one you're using now.
If you don't have a "downgraded" video card handy to try this, I might have one you can borrow. It won't fix your problem, but it's a simple test that will narrow it down.
I don't suspect your card itself, but I think there's something goofy going on with the drivers. If you can get things running normally with some other card, you'll know for sure.
From there, you will have to deal with the nVidia software...ugh. I have trod this path myself, and re-installed drivers several times. The last time was when I mysteriously lost my nVidia control panel functions... can't remember how I fixed that now, it's all a blur. It took a while, but I did it.
I have no formula other than: when you get rid of something, make sure it's out of the registry; rule out hardware; install manually when possible. That, and: if at first you don't succeed...
