Step One
Be sure to search the entire hard disk for multiple system folders, and remove all but the main System Folder.
Use the Find File DA in System 6 to find multiple system folders. Note that you may have to do this a number of times. If there are multiple system folders, Throw away any extras and empty the Trash.
Important Note: Altering a System Folder by renaming it and removing the Finder does not work with versions earlier than 6.0.5; the Macintosh may crash or hang on startup.
Step Two
Run the Compatibility Checker.
Step Three
There are two ways to proceed in this step:
Install System 7 over System 6. To do this, simply start up from the Install 1 disk and run the Installer program.
Alternatively, trash the remaining System and Finder files, rename the System Folder, and install System 7. Use this procedure if you've had problems installing over System 6. The Installer won't move any of the System 6 files into the new System Folder. You can manually move some files from the old System Folder, such as INITs, cdevs, fonts, and application Preference files or folders. Unknown or untested software may conflict.