Computer starts then shut down in 5 seconds.

[Rakeangle]

Hello, first of all excuse my bad english as it is not my first language.

I have a small system i recently built for gaming.

It was doing fine until one day i took the cpu out to clean it and re-apply thermal paste, because my cpu was at 50C idle, which i find way too high.

After i installed back the cpu and water cooler my pc never booted again.

When i hit the power button the fans start spinning, my both gtx 970 acx cooler start spinning too, the motherboard leds are on, i have no beeping sound, liquid cooler and fans, everything seems pretty normal but it will not boot and turn off after 5 seconds and repeat the same sequence.

I tried another PSU that i have,but nothing chaged so it is not that. I also cleared the CMOS, replaced battery i tried all i can imagine but it will not boot.

This is my first build by the way if anyone could help me i would appreciate it.

Case: Rosewill Legacy U3.

MB: Gigabyte Z97MX-Gaming 5.

CPU: Intel Pentium G3258 @ 4.7Ghz.

GPU: Evga Gtx 970 FTW 2 way SLI.

Ram: Corsair Vengance 8gb.

Storage: Toshiba 500gb HDD.

PSU: Corsair AX 750.

Cpu cooler: Cooler Master Nepton 120XL.

 

[Tradesman1]

Might make sure no thermal compound seeped under CPU or in the CPU socket and that there are no bent or broken pins. Also CPU placed correctly in socket

 

[Rakeangle]

Hi Tradesman1, thank you for reading and answering.

I thought of that too, so i even took the cpu out again to clean it everywhere, i also tried to clean the socket and i even checked if there were any bent pins but nothing....

 

[Tradesman1]

Could try resetting the CMOS

 

[Rakeangle]

Hi, i already did that but it wont boot, i am sure its not the PSU because i have tried different ones with the same results.

 

[Tradesman1]

Is the DRAM firmly installed, all power connections nice and snug

 

[Rakeangle]

Yes i took every part out and installed again, checked every connector, every cable everything is fine.

Dram is firmly installed as well, i even checked every slot with just 1 to mAke sure they arent faulty( even though the computer was working fine with them).

What i find strange is that even when i take both RAM sticks out and i try to boot, i dont get any Beep; shouldnt i get one when i have no sticks installed?

Thank you for the answers,

 

[Tradesman1]

Have a brief bench troubleshooting guide, might try, can be seen here:

http://www.tomshardware.com/faq/id-1753671/bench-troubleshooting.html

 

[Rakeangle]

Hello, the Motherboard have some scratches, it is a very tight build and its extremely hard to fit both graphic cards, so around the gpu areaof the motherboard there are some mild scratches.

According to your guide i should check for scratches how will these affect my boot? Mb already had these scratches and it was working well, my problems started when i took the CPU out to re apply thermal paste, i didnt touch anything else.

 

[Rakeangle]

I just tried breadboaring, the case speaker never beeped, i tried 3 different power supplies so its clear thats not the problem.

So i think its either the CPU or the MB, which could be causing the computer to shut down after a few seconds?

I feel it is a power related issue so i would say the motherboard but im not an expert, like i said this is my first build, if somone could help me to find out which part i need to replace would be greatly appreciated.

 

[Tradesman1]

Do you have access to any components you can test with? Different PSU, different DRAM, etc

 

[Rakeangle]

Yes i tried different power supplies, different Rams i have 3 gtx 970 FTW, no beep, no post so its either the cpu or the motherboard.

Im going to guess its the motherboard since ive read CPU's are not so fragile, i will buy a new motherboard and a bigger case to work with.

Thanks for your help.

 

[Tradesman1]

Let us know how it goes

 

[beesrock]

Ok I have been having the same issue with this. I've been researching and tinkering for a long long while and heres what I come to find out. I started doing the out-of-the-box build with the stock heat sink fan from Intel. Hooked everything up, ram, cpu,VC etc and it all worked flawlessly, no issues. So I assembled it all in the case. The only difference was the water cooler. I have that same exact Cooler Master 120xl cooler and it gave me nothing but problems. The whole booting and rebooting the system after 10-20 seconds and sometimes every 3-5 seconds. I reset CMOS and nothing helped.... until I put the stock Intel fan back on and then it started up with no issues. Now I'm not sure if there is any adjustment to this water cooler because it seems rather weak in fan rotating and pumping power. I would rather use a water cooler because my rig is also for gaming...

My Rig
Intel Core i7-4790K 4.0GHz Quad-Core Processor
Cooler Master Nepton 120XL 76.0 CFM Liquid CPU Cooler
ASRock Fatal1ty Z97 Killer ATX LGA1150 Motherboard
Corsair Vengeance Pro 16GB
XFX Radeon R9 290X 4GB Double Dissipation Video Card
EVGA SuperNOVA NEX 750W 80+ Bronze Certified