Where is the first place you'd look if your PC randomly shut off ??
 

My PC randomly powered off like the power supply died or something overheated. It did this twice in the last week and never before. About 6 weeks about I switched to a new coolermaster case. It should be cooler than the previous one. One of the time I powered it back on right away and it died after 2 seconds is why I thought heat. I let this bitch run all the time though... 24 hours a day. What would you look at?

The fan, especially if you run it 24 hours a day.

Your motherboard is on its last legs...mine did the same thing before I upgraded.

Power Supply

Power supply and or motherboard/cpu temperature.

Thanks for all the fast answers guys! I forget how to check the temperature but I remember reading it in the past. I'll check it after I check fans and save new power supply for last. Thanks again!

There's probably some tools that came on the driver disc for your motherboard. That's probably the easiest way to check temperatures.

most likely power supply, clean it out and make sure fan works..

Time to take it out back and shoot it...

Could be anything, you will need to go through process of elimination. Also there are no *random* things in computing. It's very definite what's fucked up, you just need to identify it..

1 - see the CPU fan, clean it if it's too dusty
2 - complete virus and malware scan just to be on the safe side (under safe mode, turn System restore off and when you're done turn it back on)
3 - turn PC off and make sure that eveyrthing on the motherboard is seated nicely in their places (slots) - RAM chips, video cards etc, simply push them gently into their slots

Like others said, check fans and power supply and also re-seat your chips and cards.

everything these guys said.

the cutout box

Power Supply

first thoughts are power supply is going bad

If you even think it's the power supply "REPLACE IT". I had a power supply go out once and it fried my entire computer. When they go bad normally there is no warning and they will often send a large power surge through your system..

Power supply's are one thing you don't want to cut corners with, buy a good one.

Check your DEP settings, and look for anything in bios or system configure set to auto reboot after crashes... maybe you are missing a bluescreen error code that you can run and find the problem.

Could be the fan..

When I used a PC rather then LT I had the same problem you just mentioned and it was my fan not working properly.

Caused PC to crash often and sometimes it wouldn't reboot. I took the side panel off to clean it and mine worked fine afterwards.

-Scott

I assume you did a full virus and spyware scan, right?

We get alot of pc's with the same problem (we have a repair department in our company). First you need to check a few things:

1 - Make sure your mainboard doesn't touch the skin of your case directly, for example, sometimes the outer skin of an usb port touches the skin of the computer case -> can cause reboots or shut down

2 - Check all fans. Make sure the CPU fan is mounted so that it overlaps all edges of your CPU, i've seen fans that where mounted badly on top of the CPU causing the CPU to overheat. If you have an active core temperature fan, make sure the rpm increases when the core temperature rises, in most cases you can check this in your BIOS. Make sure the power suply fan works and runs at it's maximum RPM.

3 - Make sure all add-on cards (PCI, AGP, ETC.....) are pushed down onto the mainboard as far as they can and are fastened with a screw.

In 90% of the shut down problems the solution is in one of the above, if not the problem is, a) RAM memory b) CPU c) mainboard d) power suply, and i would start with replacing the power suply.

Power supply!!