PC Does Not Boot

[Revolution 11]

My friend's PC will not boot. He has been away from his PC for about a year and it was working fine over the last two years and when he left it. Both the monitor and PC was completely unplugged, no Ethernet cable, no USB cables, nothing.

When he goes to start the PC now, it just sits there unpowered. There is no fans spinning, no LEDs flashing, no codes on the motherboard.

We both built our PCs with the same exact hardware models, and at the same time. I tested his PSU on my PC and my PSU on his PC. Both PSUs work on my PC but neither PSU works on his PC. His DVD drive, hard drive, GPU, and RAM were removed before we swapped PSUs. We double-checked the power cable connections before, during, and after the PSU swaps. We also swapped the main power cable to the PSU, both work on my PC, neither on his.

I am not sure what to check next. All the parts except for the motherboard and the CPU and his case/fans work on my PC fine. Any advice would be appreciated.


Here are his specs, same as in my signature.

CPU = i5-4670K at 3.5Ghz
Mobo = Asrock z87 Extreme4
GPU = AMD Radeon 7870
RAM = Crucial Ballistix 8GB 1 stick
PSU = Seasonic Platinum 660W

 

[VirtualLarry]

Sounds like a short. Did you take his mobo out of the case and put it on a cardboard / wood surface?

Unplug all the front-panel wiring, and USB ports, and headphone ports, and short the power-on pins for the mobo?

Oh, if it has been sitting for a long time, unplugged, then the CMOS battery may be dead. Try buying and installing a fresh new one. That may, on certain mobos, prevent boot.

 

[Revolution 11]

That sounds like a good start, thanks. On our motherboards, we have a power on button on the board itself. Would we still need to short the power pins?

Also, we did swap our CMOS batteries and both worked on my PC.

 

[VirtualLarry]

When he goes to start the PC now, it just sits there unpowered. There is no fans spinning, no LEDs flashing, no codes on the motherboard.

Do the DVD drive or HDD power on? (Lights / sounds / spinning / tray open/close?)

If the DVD drive tray doesn't open, with power connected and mobo turned on, then there is likely some sort of dead short. Could be a spider-web or bug in the front-panel USB wiring / ports.

 

[Revolution 11]

We have not tried your suggestion to put the mobo on cardboard yet, but we have tried to boot with only the CPU, and fans attached. The DVD or HDD could be shorted as we did not swap those but there is definitely a problem before any of those components in the mobo, fans, or CPU itself.

 

[Revolution 11]

I removed the mobo from the case, put it on cardboard, unplugged all the cables except the mobo power cable and the CPU power cable, but it is still dead.

Does the PSU also need to be out of the case? Also, does a mobo on cardboard need extra cables to the PSU besides the mobo cable and the CPU cable?

Finally, could a mobo turn on if there is no CPU or RAM plugged in? I am not talking about posting but would it turn on the LEDs on the mobo if it is the only component in a system with power?

 

[VirtualLarry]

If you remove the mobo from the case, and have just the CPU installed, and connected to both the 24-pin ATX as well as the 4/8-pin ATX12V cable, then the mobo should show SOME sort of activity, when you short the power pins. The CPU fan should at least twitch, preferably spin, and if it doesn't have RAM, then it should beep several times in quick succession if the mobo speaker is connected.

 

[Revolution 11]

What if there is no CPU installed? Would it still flash any LEDs or spin the CPU heatsink fan if it is still connected?

 

[VirtualLarry]

I don't think that the mobo would do anything without a CPU connected. Some could even be damaged by trying to power-up that way, but that's probably a rare issue.

 

[BTRY B 529th FA BN]

Bios Battery, and re-flash the bios.

 

[nk215]

Don't rule out your power supply. It may get fried the moment you plug it in.

 

[Revolution 11]

Here is a update. We already tried the BIOS battery to reset it, did not work. The power supply on both PCs was fine. We ended up ordering a Gigabyte Z97 mobo and reinstalling the OS. The new mobo worked and the system booted.

But now the old GPU was not being recognized. We swapped GPUs and my GPU worked in his PC but his GPU did not in my PC either. So we just need a new GPU as well.

Thanks for your help.