PC boot loop problem

[user999]

Hi,

I've a pc with the following configuration:
Motherboeard: Gigabyte X48-DQ6
RAM: 2X2GB ddr2 G.Skill
CPU: Intel Q9550
VGA: Nvidia 9800GTX+
PSU: Enermax modu +82 625W.

From one day to another the pc started to reset at the boot without I made any change, both in software or in hardware.
The reset that makes the loop is after the bios but before the loading of any bootloader.
Considering that I have no problems to access to the bios configuration where everything looks ok, but i can't start any test like memtest 'cause the reset, indeed, it happens in the next step after bios but before the boot check.
To find/fix this I tryed the following:
-start pc with all periphery removed (including hd, cd-roms etc..);
-remove motherboard battery and resetting cmos;
-start pc also without rams;
-start pc with another vga;
but problem in all cases persist.

What I can highlight is that during all the time the V_PHASED leds of the motherboard stay all time light up in all three colors (red, orange and green.
As I remember well, when the pc worked good, the V_Phased led, after boot, the lights went out.

I believe that my motherboard is broken but I've the doubt that also something other can be damage.
The strange thing is that from the bios everythings looks ok!!!

 

[Ketchup]

Hello user999, I actually think you have done a good job at assessing the problem. If the computer is allowing you to post with no other devices connected, but rebooting before accessing a boot option, that really sounds like a motherboard issue. Have you tried changing the boot order to make sure it won't boot off anything (a different SATA controller or port, a CD ROM, a different hard drive, a USB stick, etc)?

 

[Bubbaleone]

This boot loop is often caused by a bad PSU and your Enermax is 4-5 years old. That's pretty typical for the age when a lot of mid-range PSUs start to suffer capacitor failure, and the boot loop is a typical symptom of that condition. I'm not saying, for a fact, that's the problem but considering that you've cleared the CMOS and tested your components I'd highly suggest you test your system with a known good PSU before assuming it's a mobo failure.