When I uninstalled it, I used Add/Remove Programs, and after that, I cleared out and deleted the FS2004 folder and the files in the My Documents section. This should have erased any trace of FS2004 ever being on my computer, unless there's some hidden folder I don't know about. It also CtD when I try the flight lessons. Everything worked just fine before the uninstall and I could fly perfectly. I know I probably shouldn't have uninstalled it, but that's past, what can I do to fix it?

Specs:
AMD Athlon 3000+ 2.2ghz
GeforceFX 5200 128MB
1024 Ram
(no spyware or viruses according to spybot S&D, Norton Antivirus, and Ad-aware)