Computer Not Booting

datkins91

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Right so keep it as short as I can my computer isn't Booting.

Recently bought a new Corsair PSU, installed fine and computer Booting and running perfectly for a couple weeks. No problem.

The point I noticed trouble Booting was when I flashed my GPU incorrectly.. and had to swap the GPUs around, etc. So I could unbrick it... half way through that process... I noticed it refused to boot.

Reset the CMOS and it started Booting just fine... but now every time I turned the computer off I'd need to reset the CMOS every time.

However now when I reset CMOS it's not Booting at all. I can see there's power as the ethernet light is on.

Any suggestions at all??

Edit: Just trying the power button now and it very very briefly turns on and quickly turns off? Is it being shorted somewhere? Where's the best place to check?
 
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~Darkseeker~

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Best thing to do when troubleshooting this kind of issue is to immediately strip your machine of everything that it doesn't need to boot.

Namely, remove all GPUs (utilise on-board video if you have it), all hard drives other than your boot drive, all USB devices except mouse and keyboard (and try and use a basic mouse and keyboard if you can, rather than one with funky passthroughs or LEDS or whatever), and all but one stick of RAM.

Now you've done that, you've got a bare minimum of stuff required to boot. See if it turns on, if it does, one of the parts you've removed is faulty, you can add things back one at a time until it stops booting again, that way you know the last thing you added is the problem.

If you remove everything surplus to bare minimum and it still won't boot, try unplugging your CPU EPS power plug (the 4 or 8 pin power plug that you plug in near your CPU socket). If you remove this power plug and the system now boots, your CPU power delivery is faulty (motherboard), or your CPU has been fried.

If you've still not managed to get it to power on, try another power supply. Faulty power units do happen, and it is possible for you to buy one, have it work fine and then a few days later just stop working. Bad input power, dodgy caps or manufacturing defects are all likely causes.
 

datkins91

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Many thanks. I'very brought it into a separate room.. so no keyboard... mouse, etc.. only external connector is the power supply.

So when you say strip I assume not only disconnecting from the motherboard, but also the power connectors?
 

datkins91

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Update:

So I tried disconnecting almost everything (bar some fans) and still the same.

I decided to try my old PSU (which I tested on another computer and it works) and exactly the same thing happens. So that rules out the PSU right?

I also tried disconnecting the 8 pin 12v connector next to the CPU .. still the same thing.. so that potentially rules out the CPU too? I even removed all RAM and still the same result..

So is it the motherboard?

I hold down the power button and it just keeps powering on for half a second then off, repeatedly.
 

datkins91

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Further update:

Decided to completely remove the motherboard from the case entirely.

So it's just the motherboard, CPU, RAM .. power supply (old one) .. connect the 24 pin and 12v .. same thing.. powers briefly on and then shuts off again. Even tried removing the CPU 12v connector.. same thing.

Think it's the motherboard?
 

~Darkseeker~

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Further update:

Decided to completely remove the motherboard from the case entirely.

So it's just the motherboard, CPU, RAM .. power supply (old one) .. connect the 24 pin and 12v .. same thing.. powers briefly on and then shuts off again. Even tried removing the CPU 12v connector.. same thing.

Think it's the motherboard?
Unfortunately it sounds like you've been pretty thorough. RAM won't usually stop a machine powering on even if it's faulty - it will just halt the system at POST (fans and power on, just no display output).

If you've plugged both PSUs you've got into the motherboard both with and without the 12V power to the CPU connected, that rules out pretty much everything other than the board in my opnion.

It's a good plan when you're doing stuff like this to get it out of the case and onto a test bed of some kind like you seem to have done - I use a GPU box as cardboard is soft and non-conductive! This is a good idea as dodgy standoffs and bits of crap fallen behind the mobo tray can short connections out.


Once you've got down to this level of troubleshooting; the last test so to speak is to disconnect everything from the board other than CPU power and Mobo 24 pin power and a single fan on a fan header... power on and see if the fan keeps spinning. If it does, you're good, if it doesn't try taking the CPU power off again... if it doesn't keep the fan spinning with just the Mobo 24-pin plugged into the board, it's pretty likely unfortunately that it's a gonner :(
 
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Trotter

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Do you have an old motherboard lying around that you could snatch the CMOS battery out of and use it to test in your current board? It is a longshot but I have had a dying/dead CMOS battery cause some wind things over the years.
 

datkins91

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I tried putting in a new CMOS battery.. still the same!

I think it's a pretty good indication also it's the board given that it started playing up with having to reset CMOS each time.. and now nothing, wouldn't you say?

Thankfully for Prime I have a cheap board on its way within the next hour or so haha! Far too impatient to wait any longer! So fingers crossed it will work after this..
 

datkins91

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I'm happy to report I'm currently writing this from my computer.

It was indeed the motherboard!

A friend had a brand new MSI 970 Gaming motherboard (an upgrade for sure!) and was very unfortunate.. (cancelled the Amazon orders).

From 9am I've been flandering around and it's paid off in the end. Definitely goes to show it's worthwhile over those who'd simply just replace the entire computer! :angel:

Thanks guys, once again :)
 
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