I bought this PC used from a company looking to sell its older computers. So I put in spare HDD I had lying around, a Seagate 250GB SATA II drive. I would like to clarify that this disk had no problems when I was originally using it in a different PC. When I first got this PC, it had no issues, I installed Ubuntu MATE, however I did not like the sluggish performance of the GPU, even when using the proprietary Nvidia drivers, so I swapped the old Nvidia GPU for a newer GT-730 I had kept in a box. I figured it would be all the better as the newer GPU performed way better and consumed even less power and I could do some lightweight gaming on it. For several months it worked without issue, however it would then start to crash, regardless of which OS I had installed on it. The whole thing would freeze, causing me to have to hold down the power button in order to reboot the system. This problem has been progressively getting worse as it crashes even more often. I've tried using compressed air to clean out the internals, while that did somewhat increase the up-time of my PC between crashes, it didn't eliminate the problem. I don't know what is causing the crashes to occur and I need help, please.