New computer turns on for a second, then immediately turns off.

[icerender48]

Hey guys. I just spent the better part of two weeks getting the parts to build a new computer. I buy them, they get here, I assemble it... and it doesn't work. FML.

Basically, I have the motherboard installed (on the screw mounts, yes), the RAM in, CPU+sink is installed, the mobo is attached to the power supply, the fans are attached, and the front switches are (I hope in the right spots) attached. I have no HD attached, no GPU attached, no DVDROM attached, but I don't think it'd make a difference.

Anyways, I turn on the PSU, and the fans start going (case and CPU) and I see a couple of very fast lights flash on the mobo, and within a second (probably less)... everything stops. I can't even turn the power on again for like 15 seconds after. I've checked the PSU, and it powers up another system fine so I think the PSU is okay. I've tried to check and make sure the motherboard isn't grounding to the case by testing it outside the case on cardboard and no luck.

I've asked a lot of people and still am completely baffled as to what to try next. I've disconnected all the wires from the mobo and tried it again to the same thing.

Any help would be really nice. Thank you.

Here is my system:
RAM: http://www.newegg.com/Product/...x?Item=N82E16820227298
Mobo: http://www.newegg.com/Product/...x?Item=N82E16813128359
Processor: http://www.newegg.com/Product/...x?Item=N82E16819115037
Case: http://www.newegg.com/Product/...x?Item=N82E16811119077
GPU: ]http://www.newegg.com/Product/Product.aspx?Item=N82E16814130433


Here's manufact Mobo page: http://www.gigabyte-usa.com/Pr...oductName=GA-EP45-UD3R

 

[CoachB]

I would check the heatsink to make sure it is mounted properly. Sounds like the overheat protection built into the CPU/mobo is kicking in.

 

[dfuze]

Have you made sure that all of the motherboard's 4/8 pin power plug is inserted (not just the 24 pin plug)?

 

[icerender48]

It seems to be mounted fine to me. All the prongs go through the motherboard and I see them sticking outside firmly on the other side of the mobo.

I even tried taking the mobo out of the case and starting it on cardboard but the same thing happens.

 

[icerender48]

Originally posted by: dph1077
Have you made sure that all of the motherboard's 4/8 pin power plug is inserted (not just the 24 pin plug)?

Both the 24 pin (two parts) and the 8 pin (1, right in the socket near the CPU) are plugged in

 

[Billb2]

If your case came with a speaker make sure it is hooked up. If it didn't, get one and install it.
When a mobo won't post it will issue a "beep code" that can help isolate the problem.
It could also be the lack if a HDD installed Which a beep code would identify.
Did you use thermal paste between the CPU and cooler? Remove the protective plastic?

 

[lenjack]

Be sure to check that the cpu heatsink fan is connected to the correct header labled cpu fan.

 

[Fallen Kell]

Originally posted by: lenjack
Be sure to check that the cpu heatsink fan is connected to the correct header labled cpu fan.

And make sure that it is either a 3 pin or 4 pin fan as the 2 pin fans do not have speed monitoring and some motherboards require that it can detect and monitor the CPU fan otherwise it will go into heat protection mode and shutdown.

Out of curiosity, what power supply do you have? It might also be an issue with that. Do you have a power supply tester or no (some people have them, but it is not something most will have unless you work on a lot of PCs). It could be that there is not enough power getting to the motherboard and it shutdown when the CPU tries to really power up and draw some energy but there isn't enough for it so the system shuts down.

As others have already recommended, if you have a case/system speaker, get that connected to the motherboard to see if it kicks off some system beeps before it shuts off the power.

 

[lockmac]

I would say its the PSU. I had the exact same problem last week- tested the PSU on another PC and it worked, but it refused to work in this system for some off reason.

Try another PSU in your system (not your PSU in another system) and see how you go..