If you want to poke around inside, then try disconnecting the power lead to your HD.
The computer will fail to boot of course, but if the clicking noise has gone then you have confirmed the HD as the source.
It just might be a tired fan.
What is ransomware and how do I protect my PC from WannaCry?
What I learned from my mentor, Oscar-winning VFX supervisor Phil Tippett
Siri vs Google Assistant
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.