PC Freezes then HDD makes clicking sounds.

I doubt that it is heat and I'm glad that the diagnostic checks passed however it sounds like your psu is bad. If I where you I would just go ahead and replace it. You keep having hard drives fail and that is the most likely reason.

DLG would have informed you if the drive had ever recorded excessive temps, so that's definitely out. That said, ambient temps aren't all that matters. Depending on the model and usage, direct airflow can be necessary. If I were you I'd check the relevant SMART attribute to see how close (or not) the drive got to the threshold. Just FYI.

I managed to get the S.M.A.R.T. status of my HDD, but I'm not sure what the temperature numbers mean. How come the "worst" temp seems to be lower than the "current" one? It must be an arbitrary value refering to an actual temperature reading but I can't get any more information.

Also, there is no record under "threshold". From my point of view, everything seems fine.

Is it possible that my PSU is not supplying enough power to the system? I would be very suprised if it were the case though. I have a 750W PSU and my GPU only needs a 500W PSU. I have an SSD and HDD drive and I added a Molex fan + upgrades my rear exhaust fan for a 120mm.

SMART attributes work differently to what you'd expect. Higher is better. Values "decrease with/towards failure" and if an attribute reaches its threshold* the device is considered failed. Some values (such as "Reallocated Sectors Count") will only decrease, others like Temp and "Spin-Up Time" can go up and down.

I thought Temperature would have a non-zero threshold, clearly I was mistaken. Now that I think about it, the only time I've seen a past over-temp condition reported was with the Seagate utility when testing a Seagate drive. :/

* I believe only non-zero thresholds are meaningful.

As you can see, my HDD was replaced about 156 days ago. It's kinda new. What do you think of my temperature readings?

If everything is fine, it must be my PSU. I've never been so unlucky with hardware failures since I bought this PC... I had an HDD back when I was at high school about 7 years ago and it died last year. With my actual PC, I lost 3 disks in 4 years. At this point, it can't be bad luck lol.

Are there any more tests I can run on my HDD?

Current temp is absolutely nothing to worry about. But I'm not sure how to interpret the "Worst" value. I think it works like this: Current value of 115 = 35°, and each decrease in SMART value corresponds to a one degree increase in temp, so the "Worst" value would be 35 + (115 - 99) or 51°. The spec sheet indicates Environmental tolerance of 0-60° so again there's nothing to worry about.

One thing about WD Greens, there was a big scandal a while back about them failing prematurely due to excessive spin-down. Notice the "Power Cycle Count" is 998 but the "Power-off Retract Count" is 130592 (from hex 1FE20). This would also account for the clicking you hear. I remember WD released a tool to modify the behaviour, google "wd idle".

I think you found the problem! Some WD Cavillar users are noticing symptoms of "excessive load cycles". Brian Beeler from the storage review website is talking about a side effect of excessive load cycles resulting in "a small delay added into a data retrieval command as the head hones in on its intended spot". It's exactly what happens when I open an app or a folder once in a while.

I'm not sure if "WDIDLE3" is compatible with my HDD though. They list a couple of products on the Storage Review website, but they do not mention if It's safe to use on a WD20EZRX product...

@AddRam I'm pretty sure I have a load cycle problem. All the HDDs I had were WD Cavillar. I believe the stalling heads problem on the WD drives I had reduced their lifespan. I have no way of testing my current PSU and I'm not planning on upgrading anything for now unless it's needed.

I can modify the HDD firmware with a specific tool. It'll probably fix my problem. I would change my PSU, but I'm not even sure if it's failing. Also, I don't have a multimeter and I've never tested a PSU before.

WD Caviar has been around since the 90s or earlier, and is presently composed of the Green, Blue, and Black lines.* AFAIK only the Green line had this issue. Point being, the fact your previous drives were Caviar doesn't mean much on its own.

I would really expect a bad PSU to have other symptoms, but it can't be completely ruled out. If you're not prepared to replace it right away, backup vital data regularly (granted, you should be doing that anyway) and keep an eye out for good deals. Keep that up for at least a while even after you apply the fix.

* At least that was the case until recently; based on their webpage, it looks like they may have discontinued the Greens...