What is the first thing you would tell Ken to check in the situation that on his break, Ken is at the office enjoying some Netflix time when suddenly the sound stops coming out of his new speakers? He contacts you at the IT Help Desk by phone before he checks on anything?

Like cabling unplugged, disconnected, or cut are the physical layer issues first when troubleshooting any kind of issue, you always want to start. when the issue could have been someone tripped over the power cord and it came out of the socket, this saves you a lot of time from troubleshooting more complex scenarios. Mention the OSI model for troubleshooting methodology.