Computer turns off without warning

[Kovac]

Hello everyone 

usually i can troubleshoot some of the PC problems, but this one really got me thinking... 2 weeks ago  the computer was making this static sound then go louder and the Computer turns off, it did not turn back on so i had to wait a few mins, unplug it from the wall or turn the PSU switch Off and On again so it could start. This first happen when playing a one of my video games, then it happen while on the internet watching videos and surfing...first i thought it was a Heating problem so i check for that. No, no heating problem, CPU, MotherBoard, NorthBridge, all stay unnder 45C while working and the CPU drop down to around 15C at idle. The only i have seen at 60-70C is the Video Card but that's when i'm playing games, then it drops down to ~35C.

List of things i have done so far without any success.

Clean the dust off  the case and Motherboard with compress air.
Added 2 120mm fans to the case. it's running 5 fans now (1 front, 2 side, 1 rear, 1 top) CPU, PSU and GPU have their own fans as well. (8 total?)
Clean off and replace the Thermal Paste on the CPU.
Replaced the PSU with a bigger one, (from 650w to a 750w)
Run Anti-virus (it checked out clean)
Replaced the Hard Drive
Installed a fresh copy of Windows 7 Ultimate 64bit and all drivers
Removed the Ram and try one stick at a time
Removed the sata connectors and place them on different ports
removed the Video Card and place it on another slot
Log-on in SAFE MODE & SAFE MODE with NETWORKING
Run Windows Memory Diagnostic (no errors where found)

as you can see, i have done a lot of things and it still restarting without any warning like when you hit the reset button

PC Specs:

Operating System: Windows 7 Ultimate 64-bit
Motherboard Manufacturer: Gigabyte Technology Co., Ltd.
Motherboard Model: GA-990FXA-UD3
BIOS: Award Modular BIOS v6.00PG
Processor: AMD FX(tm)-4100 Quad-Core Processor  (4 CPUs), ~3.6GHz
Memory: 8192MB RAM
Available OS Memory: 8190MB RAM
Page File: 2149MB used, 14226MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11

Card name: NVIDIA GeForce GTX 550 Ti
Manufacturer: NVIDIA
Chip type: GeForce GTX 550 Ti

[Computer_Commando]

... the computer was making this static sound then go louder and the Computer turns off, it did not turn back on so i had to wait a few mins, unplug it from the wall or turn the PSU switch Off and On again so it could start...
List of things i have done so far without any success.
...
Replaced the PSU with a bigger one, (from 650w to a 750w)
...
Replaced the Hard Drive
...
Removed the Ram and try one stick at a time
...
removed the Video Card and place it on another slot
...
PC Specs:
Operating System: Windows 7 Ultimate 64-bit
Motherboard Manufacturer: Gigabyte Technology Co., Ltd.
Motherboard Model: GA-990FXA-UD3
BIOS: Award Modular BIOS v6.00PG
Processor: AMD FX(tm)-4100 Quad-Core Processor  (4 CPUs), ~3.6GHz
Memory: 8192MB RAM
Available OS Memory: 8190MB RAM
Page File: 2149MB used, 14226MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11

Card name: NVIDIA GeForce GTX 550 Ti
Manufacturer: NVIDIA
Chip type: GeForce GTX 550 Ti

1.  Try a different video card.
2.  If still no success, RMA motherboard to Gigabyte.

[Kovac]

Update:

I removed all the heatsink from the motherboard (marked in red) and i found that the thermal paste was kinda dryout on the bottom 2 so i clean it very good and reapply it. one thing to notice is that the top heatsink doesn't use thermal paste, it use some kind of tape, the tape have some kind of glue and had melted off down and all the connection under it where wet (some kind of moisture) so i clean/dry everything with a hairdryer, turned the tape on the other side, and reapply it, this time there is no clue to leak or melt  :thumbsup: finnaly i put everything back together and it's been stable so far, i will keep you all posted.