Pc shut down issues with out restarting?

Dollarbill87

Honorable
Dec 10, 2013
2
0
10,510
Hey,
everyone this is my first post and i have read multpie threads and cant seem to find the best answer. So right now im using a some what old rig but just upgraded a few parts and recently its just be shutting off on me like if i pulled the power plug..... I downloaded speedfan and it appears that everything is running low temp and staying cool except my GPU that can get upwards of 71c. I completely dusted out the case and all the fans seem to be working from what i can tell. The shut offs are completely at random sometimes i can be researching school work for 20 minutes or 60 mins and it can shut anywhere in between. Same with playing games as low as league of legends or as high as FF14 and again it can be 20 minutes or 60 minutes. Can the GPU be the issue here? i just got the card less then a year ago its the nvidia 670 gtx. Any help would be super helpful and much appreciated.

System details ( bought of a friend till mine is complete so not 100% sure of whats in it)
Cpu- Q6600 quad core 2.4
Gpu- Nvidia 670gtx
MB- unknown atm
500w Power supply

i wish i had more info on it. This was a frankenstein PC. Im current waiting on more parts for my build but there out of stock so i have to use this till the new year.