Mac OS X Classic Preferences

If you're not sure where, choose System Preferences and click on the Classic button.

Choose the "Advanced" button from the Classic preference panel.

If "Use Mac OS 9 preferences from your home folder." is checked, then your preference will be located under Your Computer/Users/your user name/Library/Classic/Preferences/

If "Use Mac OS 9 preferences from your home folder." is not checked, then your preference will be located under Your Computer/System Folder/Preferences/

If you never boot into Mac OS 9, then I would suggest that you check "Use Mac OS 9 preferences from your home folder." The benefit of this is that you can turn off redundant extensions such as Mouse, Display, Energy Saver, Modem, and so on. Mac OS X will override many of these extensions, so they're not necessary. The less Classic needs to load the better. The end result will be faster startup time for Classic and ideally less crashing of the Classic program.