Computer randomly turns off/restarts when playing a game (semi-fixed?)

Hamletswords

Commendable
Apr 2, 2016
4
0
1,510
I started having a problem about a week ago where my computer would suddenly turn off (no blue screen or any warning), then restart. Windows 7 would work, but if I tried to start a graphics intensive game like Blade and Soul (which I've been playing fine for months), it would do this. Initially it would let me play for an hour or so, then after it happens it would shut down immediately after starting.

I did some research, including on this site. I cleaned out my computer (it was VERY dusty). Tried fiddling around inside for loose connections.

At one point, the entire computer was having trouble starting up and reading from the harddrive. But I switched the harddrive connection and that seems to have gone away.

I came up with my own idea of underclocking my video card and it's voltage, thinking something might be up with my card. It didn't seem like overheating since it could happen so fast after the card was at like 50 degrees, but it might be. I turned the fan up to 70% steady.

Now it seems like I can play the game fine.

But I'm curious what is causing this problem. Is my video card going bad? Is it the PSU going bad (it's been fine for years, but many similar problems seem to be PSU related)?

Why would the game work on an underclocked card with 70% fan but not with the regular clocks/voltage?

Keep in mind I did many things to try to improve the performance of the game, including overclocking the card, setting the game's priority to "high" in task manager, and changing the power plan to performance and making a few recommended tweaks to that power plan.

edit: Also, I've been running the game in 1080p on my TV for a couple of months. I've run other games like that too for years without problems, but I've read that it can cause strain. Currently I'm running the game on the PC's native resolution on the TV (I use the TV as a monitor).

Could any of these things caused damage to my GPU or PSU? If so, which one. I have a feeling I'll need to replace one or the other eventually because I kind of doubt this solution I came up with will work for too long.

Any help would be appreciated!

Here's a system summary:

http://imgur.com/TqSKZES
 

Hamletswords

Commendable
Apr 2, 2016
4
0
1,510
Well, I was right about my solution not working for long. The shutdown/restarts have started again.

I've read up a lot about similar problems and it seems 95% it's the power supply.

I checked out my PSU and apparently it's a total piece of crap and it's a bloody miracle I've gotten the years of use out of it that I did get. I had no idea when I bought it that the quality of PSU makes a difference (but honestly I think I already got like 5 years out of it- which is good apparently for PSUs- go figure).

Going to pick up a decent PSU from Best Buy today. I'll update the thread with the results in case anyone's having a similar issue.