This is probably hardware, perhaps a fan that is failing. Since you
didn't say whether you have a desktop or laptop, I'm going to assume a
desktop. Open the computer case and - with the computer unplugged -
clean out any dust bunnies with compressed air. Then start the computer
but leave the case open so you can see what's happening. Carefully
observe all fans and see if you can determine where the clicking is
coming from. Don't touch anything on the inside of the computer while it
is running. If you can identify where the clicking is coming from,
replace that part.

If the clicking is coming from the hard drive area and not a fan, back
up your data immediately and replace the hard drive.

Standard caveat: Testing hardware failures often involves swapping out
suspected parts with known-good parts. If you can't do the testing
yourself and/or are uncomfortable opening your computer, take the
machine to a professional computer repair shop (not your local
equivalent of BigStoreUSA). Have all your data backed up before you take
the machine into a shop.

Malke

Sound is typical when a wire falls in the vicinity of a fan.  May be some
debris involved as well.

Find the culprit.  Take actions as needed.  Cannot be fixed with software.
Unplug the PC.  Open the case, armed with flashlight.  Find all the fans and
look in their vicinity.