I'm sure most of you do :)
 
For HDD, Windows have built in tool and here is a diagnostic tool for Intel CPUs. 
https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool
 
I'm sure similar tools can be found for AMD CPUs.
 
While waiting for my new SSDs (DAW is still down), I run the test on my 5 years old i7 2600K CPU. I think it's first time ever my CPU was stressed to 100% usage.
 
I've got one PASS and one FAIL (due to CPU temperature) last night. However, repeating the test just now, I've got 3 passes (repeating the test immediately), but the temperature was about 8 degree to the failure mark. 
 
Time to buy some thermal compound and clean up the heat sink.. perhaps changing the stock cpu fan.
 
What is your PC health result ?
 

Hi Albert,
 
FWIW, In over 20 years of working with literally thousands of machines... I can still count on one hand the number of defective CPUs we've encountered.  It happens, but it's extremely rare.
 

 I had one.  It was user induced.  I was testing or assembling something I can't even remember.  I started the machine without the CPU cooler on.  The machine shut down and then I noticed.  The CPU didn't die but a few months later it's clock speed was reduced. It was an Athlon 2600XP.   

tomixornot
I'm sure most of you do :)
 
For HDD, Windows have built in tool and here is a diagnostic tool for Intel CPUs. 
https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool
 
I'm sure similar tools can be found for AMD CPUs.
 
While waiting for my new SSDs (DAW is still down), I run the test on my 5 years old i7 2600K CPU. I think it's first time ever my CPU was stressed to 100% usage.
 
I've got one PASS and one FAIL (due to CPU temperature) last night. However, repeating the test just now, I've got 3 passes (repeating the test immediately), but the temperature was about 8 degree to the failure mark. 
 
Time to buy some thermal compound and clean up the heat sink.. perhaps changing the stock cpu fan.
 
What is your PC health result ?
 

 That's never a bad thing but sometimes a 3rd party sink doesn't always perform much better than stock coolers to justify the cost.  People assume 3rd party is always better than stock.  
  There is the "if it aint broke don't fix it" and you have to ask yourself did this utility represent a real life scenario for you?  Did you ever max out your system resources? Probably not. You should always remove dust from your system but this utility may create a paranoia in some.
 

kitekrazy1
 I had one.  It was user induced.  I was testing or assembling something I can't even remember.  I started the machine without the CPU cooler on.  The machine shut down and then I noticed.  The CPU didn't die but a few months later it's clock speed was reduced. It was an Athlon 2600XP.   

FWIW, I've seen burned up CPUs.   
I meant CPUs that died prematurely (from normal use) or were DOA.  It's very rare.
 
 
We've seen some strange things over the years.
Coffee spilled down into a laptop.  Brown goo everywhere.
Another case where a laptop display was damaged.
You could actually see the outline where someone sat on the LCD.
 
 
 
 

During the time when my internet connection was using copper telephone line, I used to stock up an extra motherboard for my office / internet PC. I'm being careful of running the power and tel line via a surge protector and plugging off the tel line out during thunderstorm. But there will be one of those days when I'll be out and the board will be fried along with the network switch and modem. The CPU, memory and HDDs usually survives :)
 
This is no longer an issue after upgrading to fiber optic line.
 
I think the diagnostic test (when driving the CPU 100%) helps to identify early signs that the heat sink needs some servicing as in my case. Usually time to remove the dusk and checking on the fans.

I've only ever encountered one malfunctioning processor for sure. It was a Celeron 300a that I OC'd way back when. After a few years, it started to malfunction. There is a second one that may be in a Dell in our server room. It is throwing internal errors on one of the CPUs. Dell thinks it is a software issue though, which can cause it, and we need to rebuild the thing to check.
 
That's all I've encountered in 30ish years of playing with computers and about 16 years of professional systems administration.
 
In terms of thermal issues, I never worry about those these days. On user PCs the usage is light enough as to rarely, if ever, be a problem and if it is, the system will signal it. We get that occasionally, especially from the ultra SFF systems. On servers they live in a climate controlled room with high quality air filtration so no issues. Also their monitoring will automatically let me know if there's an issue. On my personal system I blast the dust once a month and have the CPU hooked to a radiator that can dissipate in excess of 600 watts, so there is more than ample overhead. :)

I had an i7 3770 CPU replaced by Intel under warranty.  I was getting an intermittent, but frequent, BSOD error (don't remember the exact error).  I ran the Intel CPU test and it always passed.  I ran several other diagnostics for memory, etc, and they all passed.  I was down to shot gunning by changing hardware.  I had spare memory and that was not the problem, I had a spare Z77 motherboard and that was not the problem.  I took the power supply out of another working system and used that and it was not the problem.  Only thing left was the CPU.  I had a spare i5 CPU and tried that and it fixed the problem.  Took 2 months for Intel to replace the defective CPU.

fireberd
I had an i7 3770 CPU replaced by Intel under warranty.  I was getting an intermittent, but frequent, BSOD error (don't remember the exact error).  I ran the Intel CPU test and it always passed.  I ran several other diagnostics for memory, etc, and they all passed.  I was down to shot gunning by changing hardware.  I had spare memory and that was not the problem, I had a spare Z77 motherboard and that was not the problem.  I took the power supply out of another working system and used that and it was not the problem.  Only thing left was the CPU.  I had a spare i5 CPU and tried that and it fixed the problem.  Took 2 months for Intel to replace the defective CPU.

That's odd for Intel.