What are your full system specifications?
What PSU are you using?
Do you have a second computer you can try the graphics card on to see if the same issue occurs?
Try maybe: regedit in seach > hkey_local_machine > system > currentcontrolset > control > scroll to graphicsdrivers and click on that see if you have TdrDelay delete that than right-click new> and choose the 32 or 64 bit whatever your system is. Rename the new to: TdrDelay the "T" and "D" capital just as typed. Right-click on it and change Value data from 0 > 8 and should already be on Hexadecimal. Restart comp and see if it fixes it. If not than try changing the value from 8 to 10. Restart and see if it fixes it.
If not try and simply reseat your card, ram and cables, make sure everything is firmly pressed in even if it is clicked in properly. If it still doesn't work than try one ram stick at a time
I remember removing the graphics card and re-installing it firmly pressing everything solved it for me after going through all this driver/software stuff for days. It was because I removed it for dust cleaning and even though I replaced it, it still apparently needed re-seating