Three readers (Jeff Gilbert, Steve Jones and Jason Pellerin) have all reported a problem with the Finder Scripting Extension included with Mac OS 7.6. The symptom is a crash at startup attributable to this extension.
Most users now report that deleting the Finder Preferences file fixes this problem (see also item in Troubleshooting Mac OS 7.6).
Note: As is often the case, not all 7.6 users have this problem. Also, note that disabling Finder Scripting Extension can have its own problems (leading to multiple desktop printers appearing on your desktop, as reported on this page several months ago).