Something terrible has happened to my PC, sudden loss of performance

[The Toaster]

Let me explain my predicament...

So I built my PC back in September 2013 with the following specs:
Motherboard - MSI Z87-G45
CPU - Intel Core i5 5670k (Stock Cooler)
GPU - EVGA GTX 770 Superclocked W/ ACX Cooler
RAM - 2 x G.Skill Ripjaws X 4GB
HDD(s) - 1TB HDD + SanDisk 64GB SSD

And it has run smoothly since then. But a few days ago something happened, I had a game minimised (Dead Space 3) and upon re-opening the game, the GPU fans went to 100%, and there was no signal from the GPU itself. I was forced to manually shut down the PC by holding the power button as even the trusty case reset button was not working. Upon turning the system back on, the GPU fans again went straight to 100% and no signal came out of the card. Fearing the worst, I removed the card (which showed no sign of failure) and decided to try the second BIOS on the card; upon re-insertion the system jumped into life and has seemed fine since then.

Today however, the performance has seemed to fall exponentially. For example I ran the Passmark PerformanceTest and found that it barely got through the 2D graphics stage, although 3D graphics was not too bad - The results show that every part of the PC seems have suffered, the CPU got a score less than an Intel Core 2 Duo and the GPU less than half the score of the GTX 680.

So my question is this - clearly something has broken, or has failed in some way, all the components are still in warranty and so can be sent back if needs be. But what do you think the problem is?

 

[badboyrog2]

''CPU - Intel Core i5 5670k (Stock Cooler)''

this is not a good idea to let a stock cpu cooler kill the cpu.........always install an aftermarket cpu cooler

check in the bios if you can see the temperature of cpu and gpu , also check the voltages reading if they are normal
let me know

 

[The Toaster]

I use MSI Afterburner to monitor temps and I have found that the CPU rarely exceeds 60 degrees, the GPU can hit 80 but rarely. Idle CPU temps are around 32. I will also now check on the bios for the voltages.

 

[The Toaster]

Ok so the BIOS tells me the CPU is at 46 degrees, if MSI Afterburner is off by 14 ish then the CPU may have been hitting around the 75 mark under load. The voltage reading was 1.056V

 

[badboyrog2]

''The voltage reading was 1.056V ''

??????
i need all the voltages

see an example here
http://www.frozencpu.com/images/awards/psu_testerr2.jpg

 

[The Toaster]

Sorry, the voltages are as follows

CPU Core - 1.064V
CPU I/O - 1.016V
System/3.3V - 3.392V
System/5V - 5.080V
System/12V - 12.232V
DRAM - 1.488V

 

[badboyrog2]

so the temps and voltages look good so far.........
about the cpu core voltage usually is approx 1.15v but it can differed a bit
i suspect the msi afterburner , can you remove this apps and see if it fix the problem?
after removing this apps go in the bios and save and exit with the default settings
let me know

 

[The Toaster]

I have uninstalled MSI Afterburner, and there is no difference...

 

[badboyrog2]

do you set the bios to default value and save/exit ?

 

[The Toaster]

Yes I have, it made no difference. I have also put the graphics card into another system and it works fine in there. So it could be the motherboard or even the CPU?

 

[badboyrog2]

it can be a gpu driver conflict with the game you played
can you do a clean uninstall of the gpu driver ( i mean a full removing of the driver even the files associated )
and reinstall it
let me know

 

[The Toaster]

I can't remove physX System Software, it seems to be corrupted (no amount of registry editing and other tricks have succeeded). I'm going to bite the bullet and reinstall windows

 

[The Toaster]

IT LIVES!
So reinstalling windows has fixed the problem, so the problem must have been with the physX drivers (or some other software related issue) that got corrupted when the game crashed.
Thanks for all your help.