Hello everyone , So been about 2 months im facing a problem that whenever i play or even doing nothing my pc freeze , with a random solid color , sometime buzzing in the speakers and i have to force restart the pc  , been searching all over the forums before making this topic , so i hope i can find some help .
PC specs
Motherboard - ASROCK z77 formula OC
Processor - i7 3770k intel
GPU - GTX 780 evga - "3 years ago and out of warranty" 
PSU-Cooler master 725 extreme
RAM - 3*4 Hyperx blue
 
I've narrowed the problem that its in the GPU for sure and here what i've done so far :
I tried to use processor gpu to test if i will get that freeze - got none
I did check each ram in a different slot alone with GTX780 on ... got freezes every single time with every slot and every single RAM
I did borrow another PSU from a friend "thermaltake 720w" got the same freeze
tried another HDD , Got freezes
Have used fresh windows install both 7 and 10 , got freezes 
Used different drivers with clean install in safe mode and sweeper "v 385.41 and v 388.71 and v 387.92" and i noticed i get freezes more often with v388.71 driver
ofc i ran memtest86 and checked for bad sector , updated Motherboard's bios 
 Edit : i never used overclock for the gpu since i bough it , but when the problem started i tried to underclock it a little to see if there is any difference and i got freezes again
 
So any ideas guys to fix it , and i guess if its dead or not ...
Notice " I live in Egypt and u know there is no Evga branch in egypt to send it there to take a look" and i bough it from amazon online 3 years ago "
Thanks in advance and sorry for bad english

Sajin
Looks like you didn't try testing the card in another pci-e slot.

Sorry i forgot to mention that i tried testing it in dif 3 slots 
 

Sajin
The issue may be coming from your motherboard. I'd suggest testing with another video card that draws the same amount of power as the 780.

Im pretty sure its not da motherboard even i didn't try another GPU on it , I guess its a very long shot ... What if its the GPU ? is there anything else i should try ? anything u recommend ? ... 
thank's for your help tho 

Sajin
If it's the gpu I'd just buy a new card since you're out of warranty.

Ohh that's sad , anw thanks for your help man ... appreciate it 

pilgreenal
I ran into the same problems with my 760 FTW. I still *rarely* get lockups but by using an older driver and reapplying thermal paste/pads to the heatsink on the gpu its helped a lot.

I have tried that ,didn't help :(

You mentioned 'underclocking' the GPU. Did you also reduce the memory clocks?


Yeah i've tried that,didn't work either