Most hardware failures that display a Sad Macintosh error will do so before the floppy drive or hard drive start spinning.  If a Sad Macintosh appears after the disk starts spinning, the first digits of the error code are usually '0F' and often indicate corrupted software.  If you get this error code, try restarting the Macintosh with the Option and Command keys held down to rebuild the desktop file.  You also may be able to fix these problems by reinstalling system software.