Computer can't power up?

[BIGseXXXy]

A month ago I assembled a computer that's been running smoothly and silently until last night. Here are the specs:

Mobo: Gigabyte H87N WIFI ITX
CPU: Core i5 4670
GPU: Gigabyte Nvidia GTX760 4GB 5DDR
RAM: Corsair Vengeance Pro 2x8Gb 1866MHz
SSD: Corsair Force LS 240GB SATA 3
HDD: Toshiba 500GB
PSU: Corsair CX500M
OS: Win 7 Ulti 64bit

Last night, it died suddenly while I was playing D3. When I pressed the power button, all I got was a black screen (monitor itself is still responsive) while my GPU fans started spinning VERY loudly and quickly. All other fans, such as casing and CPU fans, did not operate. There is no smell of burnt plastic/rubber.

I intend to open it up and reconnect my GPU after I get home from work, but if anyone has any advice for me, I would thoroughly appreciate it.

[blackblade]

A month ago I assembled a computer that's been running smoothly and silently until last night. Here are the specs:

Mobo: Gigabyte H87N WIFI ITX
CPU: Core i5 4670
GPU: Gigabyte Nvidia GTX760 4GB 5DDR
RAM: Corsair Vengeance Pro 2x8Gb 1866MHz
SSD: Corsair Force LS 240GB SATA 3
HDD: Toshiba 500GB
PSU: Corsair CX500M
OS: Win 7 Ulti 64bit

Last night, it died suddenly while I was playing D3. When I pressed the power button, all I got was a black screen (monitor itself is still responsive) while my GPU fans started spinning VERY loudly and quickly. All other fans, such as casing and CPU fans, did not operate. There is no smell of burnt plastic/rubber.

I intend to open it up and reconnect my GPU after I get home from work, but if anyone has any advice for me, I would thoroughly appreciate it.

Scan motherboard for blown capacitors (they'll be bulging).
Second thing is to check the power supply. I don't think it's a PSU issue because there's power going to the GPU, (but not the mobo, apparently.)

[Fpsdoug]

As the other guy said look at the MB.

Other then that try resetting the CMOS with a jumper/screwdriver (will be in mb manual). Take one ram stick out. Try to boot. Alternate the one ram stick, to see if one went bad.

One ram stick not be able to run at its rated timings anymore and you might not be able to boot because of it. Clearing CMOS might get you a boot if alternating ram sticks fails.

[Cyrops]

Check transistors on MB.
Then unplug everything from mobo, take out the RAM, leave the CPU in and try to boot, see if the MOBO itself starts up.

[BIGseXXXy]

Update: Have disassembled my computer. At first glance there do not appear to be any bulging or leaking transistors/capacitors, but I'm taking out the mobo for a closer look.

Also, I have disconnected everything 'cept the power supply and casing power button from the mobo. When I press the button, things seem to run, but only briefly. Then it fails again and goes limp.

Will update as I check more.

[Deleted]

Just because the fans spin up etc does not mean that the PSU aint dead, a friend of mine had the exact same issue and it was his PSU that snuffed it, yes Corsair are top notch when it comes to power supplies but the CX Builder series are low end budget and have a pretty bad rep... my money would be on the PSU, could you try and borrow another PSU to test it?

[BIGseXXXy]

Sadly don't have access to another PSU. All I have is a laptop besides my PC.

- - - Updated - - -

Resolved! I just took apart everything and put it all back together again, so obviously something was just loose.

In the process I managed to get a HUGE load of cable management in, so it wasn't all a waste of time.

Still, thank you all for your time and advice.

[BIGseXXXy]

Problem seems to have returned 2 days later. Here is a better description of it:

My computer can randomly die while in-game. After I try to turn it back on, the screen remains blank while the GPU fans start to go into overdrive (casing and CPU fans do not activate). 2 days ago, turning the power switch off and then back on did not solve the problem, but this time it does. I would rather not have to resort to this, though.

The first time this happened, disassembling and then reassembling all parts solved the problem. I did not observe any blown/leaking/bulging capacitors and trasistors, or any burnt smell or melted components. As I speak, my computer died twice in quick succession then saw me through 3 hours of SoO without a hitch. IKR :S

[Cyrops]

Problem seems to have returned 2 days later. Here is a better description of it:

My computer can randomly die while in-game. After I try to turn it back on, the screen remains blank while the GPU fans start to go into overdrive (casing and CPU fans do not activate). 2 days ago, turning the power switch off and then back on did not solve the problem, but this time it does. I would rather not have to resort to this, though.

The first time this happened, disassembling and then reassembling all parts solved the problem. I did not observe any blown/leaking/bulging capacitors and trasistors, or any burnt smell or melted components. As I speak, my computer died twice in quick succession then saw me through 3 hours of SoO without a hitch. IKR :S

If you are comfortable, and have experience, open up PSU (UNPLUG FIRST) and inspect it's transistors.
Also if you have integrated graphics, try that without GPU.