Hard drive failure sounds at link below. See if you can match yours up to the sounds presented in the video. I'd start saving / backing up any data like pictures, & Documents if you don't already have a backup schedule.

Here is a link that might be useful: Failing hard drive sounds

do you only hear this sound on particular website? If so could it be an ad or something on that site that has sound? I had that happen once to someone I was helping and once they visited that site it opened the thing that made the sound and it minimized and then they would hear it even when on other sites because they did not realize it was opened and minimized.

Just to see if it could be you might try muting your speakers or see if you can hear that sound coming from the speakers or identify exactly where the sound is coming from, the tower?

You can run some test to see if your hard drive health is bad. Belarc has a test but there should be some specific for you on the HP site for your particular model.
Belarc Advisor

How to Check the Health of your Hard Drive

No disrespect, but I have never heard of clunking as a sound from a computer system. From a motor vehicle yes, but a computer system no. That's a new one for me.

I like the idea of the site generating the noise.

DA

7600 rpm Hard Drive when needing defrag on my old desktop has clunked for years. Run a defrag & no clunks for a while.

Clunking sounds can happen. "Clunk of death" they call it. Could be the reason the users computer is slow too. Not to be confused with "Click of death" sound.

Let's not confuse an aggressive, forceful click with a clunk. A clunk is distinct. Perhaps like one of the musical notes used in Law and Order.

DA

if it is the hard drive you might want to give a look at spin rite over on grc

SpinRite

but you really need to determine just where that sound is coming from that would definitely help

OP has not returned so we may be replying to the wind LOL

Have you ever run disc clean-up, followed by the defragmenter? If not, that would cause slowness. How about updated antivirus software?

No idea about the clunking unless it just happens if you try to play the wrong suit.

the op's computer may have "clunk out"

"clunks" are in the ears of the hearer. LOL!