Complex sentence: The sad Mac icon was displayed, along with a set of hexadecimal codes that indicated the type of problem at startup in place of the normal Happy Mac icon, which indicated that the startup-time hardware tests were successful.
Split into simpler sentences: The sad Mac icon was displayed, along with a set of hexadecimal codes that indicated the type of problem at startup. This was used in place of the normal Happy Mac icon, which indicated that the startup-time hardware tests were successful.