New build starts to crash -- which part is broken?

[Superphilipp1987]

Hi everybody! I hope this is the correct forum for my question.

I built my parents a new machine for christmas. These are the new parts (all purchased new from alternate.de):

Mainboard: Asrock 880GM-LE (AMD 880G, SB710)
CPU: AMD Phenom II x4 965
CPU cooler: Arctic Freezer 64 Pro
RAM: cheap-ass G.Skill 2x2GB DDR3-1333
SSD: Mushkin Chronos 120GB
PSU: Thermaltake Munich430W

Add to that their old 2GB SATA HDD (Samsung I think) and my old SATA DVD burner. There's no dedicated graphics card, but the old HD Samsung monitor is connected to the on-board GPU using HDMI. All of the old parts have previously worked fine in other machines. I installed Win7 HP 32bit from my parents' previously purchased license.

Now here's the problem:
From day one, the computer had these types of crashes: Out of the blue, the monitor would switch to black, the power LED would turn off, and all fans would keep running. No key combination would result in anything (ctrl+alt+del, sleep key). Pushing the power button would make the computer turn off immediately.

These crashes have occured with increasing frequency. You'd get them every couple of hours at first, but by now they will happen a minute after switching on the PC at most! They occur independently from the OS, even if I just load the BIOS setup and stay there for 30 seconds — so it's apparently not a software issue at all.

Solutions I have already tried:
We have disconnected one at a time: The HDD, the DVD burner, both RAM modules. Those can't be the cause of the problem (at least not on their own).

We have checked the CPU cooling with a full stress test in the beginning: half an hour on Prime95 and it never gets above 65°C (150°F). Specifically, when it crashed from the BIOS setup, the temperature was around 50°C (122°F), as taken from the BIOS readout. This does not seem to be a CPU temperature issue.

I'm thinking it's a busted CPU, mainboard and/or PSU. Can anybody rule something out from the symptoms I described? Is there anything I can try to fix the problem myself? I really don't feel like spending the next month or so unnecessarily returning a dozen parts one at a time by mail. And unfortunataly I don't have any replacement CPUs of PSUs lying around that I could check.

Thank you very much!

 

[o1die]

You're going to have to do some educated guesswork yourself. You may have a heat or short issue with the power supply. Check your backplate for squareness and excess metal touching somewhere in the port area. Rma the motherboard if asrock will issue you a number, but until you try another power supply, it might be a waste of time. Good luck.

 

[Poprin]

I agree with o1die my first feeling would be power supply here, if you've got a spare I'd try swapping that out first to eliminate it. You can test the HDD and RAM relatively easily with a HDD disgnostic and memtest to see if they kick out an error. Failing that it probably is the mobo.

 

[Superphilipp1987]

So you think those (PSU, mainboard) are more likely than it being a CPU issue?

The RAM and HDD I have already eliminated.

 

[o1die]

Cpus rarely fail except in a lightening strike or when the heatsink comes loose, but Intel's speedstep will throttle it down automatically to reduce heat damage.

 

[Superphilipp1987]

Still might be a dud. It's new after all.

 

[o1die]

The power supply is the easiest place to start; I sometimes find them used on craigslist for $10.

 

[Superphilipp1987]

Best answer selected by Superphilipp1987.