PC randomly shuts off for no apparent reason without any warning/error message

[Zhulrak]

So as of 2 days ago, my PC keeps randomly shutting off for no apparent reason. I could be using chrome, playing games, or just afk, and it shuts off without warning or any error screen. I have no idea what this could be or what to even search for, so if anyone here has any idea of what the problem could be please let me know.
OS: Windows 8.1 latest updates Intel Core i5-2500k Nvidia GT 520 8GB RAM 600W PSU Asus P8H67-M LE motherboard

[Vladimeir]

So as of 2 days ago, my PC keeps randomly shutting off for no apparent reason. I could be using chrome, playing games, or just afk, and it shuts off without warning or any error screen. I have no idea what this could be or what to even search for, so if anyone here has any idea of what the problem could be please let me know.
OS: Windows 8.1 latest updates Intel Core i5-2500k Nvidia GT 520 8GB RAM 600W PSU Asus P8H67-M LE motherboard

Sounds like overheating.

Check the fans. Make sure they are working optimally.

Check the general air flow to and from your computer. Possibly clean any dust from the inside. Maybe try relocating it to an open area. See if the problem persists.

While it's most likely overheated (it being summer and all) it could also potentially be the power supply dying. (Or the powersupply overheating.) So do all the above for the powersupply as well.

[Daerio]

Almost definitely overheating.

[Herecius]

Definitely sounds like overheating. Clean it inside and out, and re-set the CPU on a fresh bit of thermal paste. Clean off the old stuff very gently with a q-tip and isopropyl alcohol before reapplying the new paste.

If this isn't the problem, it should be beneficial for your computer anyways, so can't hurt to do it regardless.

[Zhulrak]

A quick glance inside the case and every fan seems to be working properly so I don't think that is the problem. I just checked the temperatures using CPUID and everything seems to be around 100 degrees fahrenheit which I assume is alright, except the temperature of the processor itself is a little over 200 degrees so I'm thinking that is the issue. The fan is working fine on it so maybe all I need to do is get more thermal paste?

[Herecius]

A quick glance inside the case and every fan seems to be working properly so I don't think that is the problem. I just checked the temperatures using CPUID and everything seems to be around 100 degrees fahrenheit which I assume is alright, except the temperature of the processor itself is a little over 200 degrees so I'm thinking that is the issue. The fan is working fine on it so maybe all I need to do is get more thermal paste?

Not 'more' necessarily, but carefully cleaning off the old paste and then just reapplying fresh stuff (not too much!) should be fine. The most important part there is being sure to clean the old paste off first with a q-tip and alcohol, otherwise the new stuff won't help much. It's safe to assume you aren't overclocking anything of course, right?

[SidFwuff]

A quick glance inside the case and every fan seems to be working properly so I don't think that is the problem. I just checked the temperatures using CPUID and everything seems to be around 100 degrees fahrenheit which I assume is alright, except the temperature of the processor itself is a little over 200 degrees so I'm thinking that is the issue. The fan is working fine on it so maybe all I need to do is get more thermal paste?

Your CPU is over 200F? As in 100C?!

Yes.

That would be it.

I wouldn't think thermal paste would need replacing- I'd think the heatsink's screws may be loose, or the fan is failing. Cleaning and re-applying some new thermal paste wouldn't hurt though, as that'd let you check the heatsink and fan.

[Zhulrak]

Yeah I thought 200F was a bit too high, lol. I'll get some more thermal paste today and clean off the old stuff, that should probably help. The fan though seems to be functioning fine so I do not think the problem lies there. @Herecius No I am not overclocking anything currently.

[Vermicious]

Anything much above 70c (158F) is suspect for most Intel CPUs... so yeah it's something to do with your CPU cooling.

[Septik]

Yeah I thought 200F was a bit too high, lol. I'll get some more thermal paste today and clean off the old stuff, that should probably help. The fan though seems to be functioning fine so I do not think the problem lies there. @Herecius No I am not overclocking anything currently.

make sure u clean out the actual heat sink, look between the fins and make sure there is no dust build up in there! fan may appear clean but in between the fins is where fine dust tends to collect.

[Zhulrak]

Cleaned out the heatsink/fan and reapplied the thermal paste and the processor is now operating at about 50C-65C, which still seems a little high, but I'm guessing it will take a little bit for the paste to fully set in.

[Zhulrak]

If that's idle then you either have air bubbles or applied to much paste. If that's while doing stuff then you're where you want to be.

Yeah it is still running a bit higher then I think is good, plus I'm putting a new graphics card in there soon so I think I need to get better ventilation going as well. The paste I used was probably 10 years old and I have no idea how good it is, so I'll probably get better thermal paste and some internal fans, since the only one I have seems to be running at about 300 rpm. Also does more fans make a huge difference? I have space for 3 if I'm not mistaken, and I'm only utilizing one spot for one that I think is underperforming.