i dont think that you need to format ur hdd
for me i`ll do this step :-

1. check temp inside pc when idle and max usage (check idle & when you run the game)
2. check thermal paste, if possible .. clear all the dust at the heatsink
3. check psu fan, sometimes it`s stuck coz of lizard (kena this before)

for me, if my pc restart normally coz of tempeture, dunno yours, maybe can try