My computer is restarting randomly for no reason at all. I could be doing something as simple as surfing the web, or playing GTA V under full load, and it just restarts. I don't know why it does this. My old computer did the same thing, so I bought pretty much all brand new parts aside from the GPU and HDD. Now the old computer doesn't but my new one does. I don't know whether or not its the HDD or the GPU. I'm kinda leaning twords the HDD because I bought it online on eBay, used, and also my windows isn't booting anymore on that hard drive. And I bought my GPU on NewEgg New. The Hard Drive is a Western Digital 1TB Green and the GPU is a R9 270 Power Color. Please try and help my figure out what it is because I don't want to go out and buy both, I'd rather just buy one and not have to spend an extra $150 on a GPU if it's the hard drive. Thank you in advance!