Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
If you exit from the main screen you must use Ctrl+Shft+Q.
Use Ctrl+Alt+Del to check your open processes for extra copies running in the background.
You're running Windows 7, I expect and Major Magee is right on it: CFS3 doesn't properly shut down in Win7 and leaves a cfs3.exe process running. This happens whether you use the menu to shut down or Alt-F4.
As the Major says, Control-Shift-Q will shut the sim down cleanly.

Guys,
I think under Windows Vista and under Windows 7 that to get to the "Task Manager" the keyboard shortcut is:
Ctrl + Shift + Esc