Computer won't start, starts when I unplug 12v 4-pin CPU connector

[heintz_nick]

Yesterday I was rendering a high-resolution 3D image (don't know if it's related, my CPU and GPU weren't overheating at the time, [CPU 46c][GPU 32c]  and my computer suddenly shut down. I tried starting it and after half-a-second it shut back down. The only time it will actually "start" is when I disconnect the 12v 4-pin CPU connector, but obviously my computer won't work with out a CPU. 

 I built this computer around a year ago (everything new except for the power supply). Around 5-6 months ago I had to replace the motherboard... It was doing this EXACT same thing.

I don't know what is wrong (I'm only 16 and have limited troubleshooting experience) and I can't test to see if it is the PSU, GPU, or CPU because I don't have any other ones! And I can't barrow any from friends because I live in a small town and I don't know anybody who knows ANYTHING about computers (can't tell you how many times I've said memory and people think I mean HDD space... Then I explain and they don't know what I'm talking about).

I have searched the Internet (on my phone) for hours and nothing has worked. Does anybody know what is wrong? Any help is appreciated

System Specs:
-MB: MSI 760GM-P35
-CPU: AMD Phenom II 1075, 6-core, 3.0GHz
-GPU: NVIDIA GeForce Gtx 460, 786mb GDD5
-Memory: Kingston 4gb (2x2) HyperX T1 DDR3
-HDD: Seagate Barracuda 7200.9 120gb (old, came with original computer bought when I was 11), Seagate FreeAgent 1TB, Seagate Expansion 2TB
-Power Supply: RocketFish 500w, dual +12v rails with 18A load (I didn't pick this one, my parents got it at Bestbuy without me there)

 

[gokanis]

You can buy a $10-$20 dollar power supply tester and see if your PSU is ok. It sounds like it took a jump off a cliff.

http://www.xoxide.com/coolmax-ultimate-psu-tester-lcd.html

Something like this would work, you can find them cheaper, if you have a radio shack around they may have one. Very easy to use.

 

[heintz_nick]

I know, I have been meaning to get one but the closest RadioShack is an hour away. But I will get one online, thanks.

But since it may not be my power supply and it will take a few days for the tester to arrive (I will probably order it tomorrow and it takes awhile to get packages at my house because I live in the middle of nowhere) if anyone has anymore answers, ideas, and/or suggestions, they would all be appreciated

 

[arthurh]

@ heintz_nick

I think your PSU is causing you to have failed M/BDs because when it gets under a load it can not keep up with the demand on it. As it ages the electrolytic capacitors in it start to fail and it just can not put out the continuos power that you need. This is especailly true with inexpensive PSUs.

Compare THIS PSU specs to yours and I think you will see the difference and this is rated lower in watts than the one you have. Note that this is not the BEST PSU you could buy either.

Thou your parents meant well it is unfortunate that they happen to pick that particular PSU for you. I would not recommend that PSU to any one.

Good luck to you.

 

[heintz_nick]

@ heintz_nick

I think your PSU is causing you to have failed M/BDs because when it gets under a load it can not keep up with the demand on it. As it ages the electrolytic capacitors in it start to fail and it just can not put out the continuos power that you need. This is especailly true with inexpensive PSUs.

Compare THIS PSU specs to yours and I think you will see the difference and this is rated lower in watts than the one you have. Note that this is not the BEST PSU you could buy either.

Thou your parents meant well it is unfortunate that they happen to pick that particular PSU for you. I would not recommend that PSU to any one.

Good luck to you.

1st, thank you for your response, extremely helpful and altogether well said. And ya, I know that they meant well and considering my last PSU (which came with my computer) was only 250w it was an improvement, even if by default

2nd, love that you used Newegg that is actually where I got all my hardware when I built my computer because they are usually (in my experience) cheaper, or more accurately, less overpriced.

 

[arthurh]

I have been buying from Newegg since 2002 for almost all of my needs computer related. I do not particularly like the rebate program, Tigerdirect burned me once but never again. I wish they still had FedX as their main shipper thou UPS is getting better.

Last but not least, thanks for your appreiciation and I hope all goes well with your future goals!