The fastest way to do this for InDesign CS2 (and any CS2 program) is to quit the program, then hold down Command-Option-Shift-Control immediately after starting it up again, and keep those keys held down. (On Windows, hold down Control-Alt-Shift.)

If you mashed on those keys quickly enough, you‚ll get an alert when the splash screen appears offering to Delete InDesign Preferences File?. Click Yes, but don't release the modifier keys while you do so, because you're going to get a second alert to which you should also click Yes. (It's part of the InDesign voodoo.